Gobolinux

http://www.gobolinux.org/?page=at_a_glance Multiple versions of a program can be maintained simultaneously, so you can alternate between them as you desire, or even use both at the same time when necessary.

/Programs] ls -l OpenOffice total 8 drwxr-xr-x 9 root root 4096 2005-09-22 01:07 1.1.4 drwxr-xr-x 3 root root 4096 2005-09-23 04:36 2.0 lrwxrwxrwx 1 root root    5 2005-09-23 04:36 Current -> 2.0

/Programs] ls -l GTK+ total 12 drwxr-xr-x 10 root root 4096