Spend some time last week setting up Joe Marcus' tinderbox scripts. Works really well, and enables me to test ports builds on different FreeBSD branches. In addition, it makes installation packages that I can deploy over my servers, hence saving build times.
I've setup build environments for: RELENG_4, RELENG_5 and the newly branched RELENG_6.
Spent some time HTMLizing the README file, here it is.
Read more and get it here.