This NPE is happening pretty often for me (every 10 minutes?). I have a bunch of multi-configuration projects and I have the "Number of Builds" column visible in the default view that I am using:

Aug 26, 2012 5:37:53 PM hudson.ExpressionFactory2$JexlExpression evaluate
WARNING: Caught exception evaluating: it.getStats(job). Reason: java.lang.NullPointerException
java.lang.NullPointerException
at hudson.plugins.projectstats.NumBuildsStats.compute(NumBuildsStats.java:51)
at hudson.plugins.projectstats.column.NumBuildsColumn.getStats(NumBuildsColumn.java:53)
at sun.reflect.GeneratedMethodAccessor85.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.commons.jexl.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:258)
at org.apache.commons.jexl.parser.ASTMethod.execute(ASTMethod.java:104)
at org.apache.commons.jexl.parser.ASTReference.execute(ASTReference.java:83)
at org.apache.commons.jexl.parser.ASTReference.value(ASTReference.java:57)
at org.apache.commons.jexl.parser.ASTReferenceExpression.value(ASTReferenceExpression.java:51)
at org.apache.commons.jexl.ExpressionImpl.evaluate(ExpressionImpl.java:80)
at hudson.ExpressionFactory2$JexlExpression.evaluate(ExpressionFactory2.java:72)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$3.run(CoreTagLibrary.java:134)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$2.run(CoreTagLibrary.java:105)
at org.kohsuke.stapler.jelly.JellyViewScript.run(JellyViewScript.java:81)
at org.kohsuke.stapler.jelly.IncludeTag.doTag(IncludeTag.java:146)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:270)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:161)
at org.apache.commons.jelly.tags.core.ForEachTag.doTag(ForEachTag.java:150)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:270)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$2.run(CoreTagLibrary.java:105)
at org.kohsuke.stapler.jelly.CallTagLibScript.run(CallTagLibScript.java:119)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:161)
at org.apache.commons.jelly.tags.core.ForEachTag.doTag(ForEachTag.java:150)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:270)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$1.run(CoreTagLibrary.java:98)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$2.run(CoreTagLibrary.java:105)
at org.kohsuke.stapler.jelly.CallTagLibScript.run(CallTagLibScript.java:119)
at org.kohsuke.stapler.jelly.groovy.JellyBuilder.doInvokeMethod(JellyBuilder.java:283)
at org.kohsuke.stapler.jelly.groovy.Namespace$ProxyImpl.invoke(Namespace.java:92)
at $Proxy36.projectView(Unknown Source)
at lib.JenkinsTagLib$projectView.call(Unknown Source)
at hudson.model.View.main.run(main.groovy:14)
at org.kohsuke.stapler.jelly.groovy.GroovierJellyScript.run(GroovierJellyScript.java:66)
at org.kohsuke.stapler.jelly.groovy.GroovierJellyScript.run(GroovierJellyScript.java:59)
at org.kohsuke.stapler.jelly.IncludeTag.doTag(IncludeTag.java:146)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:270)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.CallTagLibScript$1.run(CallTagLibScript.java:98)
at org.apache.commons.jelly.tags.define.InvokeBodyTag.doTag(InvokeBodyTag.java:91)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:270)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$1.run(CoreTagLibrary.java:98)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$2.run(CoreTagLibrary.java:105)
at org.kohsuke.stapler.jelly.CallTagLibScript.run(CallTagLibScript.java:119)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.CallTagLibScript$1.run(CallTagLibScript.java:98)
at org.apache.commons.jelly.tags.define.InvokeBodyTag.doTag(InvokeBodyTag.java:91)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:270)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:99)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.tags.core.CoreTagLibrary$2.run(CoreTagLibrary.java:105)
at org.kohsuke.stapler.jelly.CallTagLibScript.run(CallTagLibScript.java:119)
at org.kohsuke.stapler.jelly.CompressTag.doTag(CompressTag.java:44)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:270)
at org.kohsuke.stapler.jelly.JellyViewScript.run(JellyViewScript.java:81)
at org.kohsuke.stapler.jelly.DefaultScriptInvoker.invokeScript(DefaultScriptInvoker.java:63)
at org.kohsuke.stapler.jelly.DefaultScriptInvoker.invokeScript(DefaultScriptInvoker.java:53)
at org.kohsuke.stapler.jelly.JellyClassTearOff.serveIndexJelly(JellyClassTearOff.java:107)
at org.kohsuke.stapler.jelly.JellyFacet.handleIndexRequest(JellyFacet.java:127)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:563)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:659)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:625)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:659)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:488)
at org.kohsuke.stapler.Stapler.service(Stapler.java:162)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:45)
at winstone.ServletConfiguration.execute(ServletConfiguration.java:248)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:333)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:376)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:95)
at hudson.plugins.greenballs.GreenBallFilter.doFilter(GreenBallFilter.java:58)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:98)
at hudson.plugins.audit_trail.AuditTrailFilter.doFilter(AuditTrailFilter.java:66)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:98)
at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:87)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:47)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:166)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.basicauth.BasicProcessingFilter.doFilter(BasicProcessingFilter.java:173)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at jenkins.security.ApiTokenFilter.doFilter(ApiTokenFilter.java:63)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:66)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:50)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:331)
at winstone.RequestHandlerThread.processRequest(RequestHandlerThread.java:215)
at winstone.RequestHandlerThread.run(RequestHandlerThread.java:138)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)