Hudson is great for compiling the subversion trunk.
But it would be nice if it could compile from a tag.

Step:
1) developer creates a tag name
2) developer access hudson, selected their project. selects build on demand
3) developer enters the tag name to build. (REL_app_RC1)
4) hudson will checkout can compile the tag
http://svn.repos/project/app/tags/REL_app_RC1

This is very handy for release management.