I just finished playing around with getting Apache's reverse proxy setup for our development department. Now we don't have to worry about configuring a bunch of firewall ports to have external access to development machines.
I'm on a continual quest to figure out high availability and load balancing solutions on the cheap. Once I get all this stuff figured out, I'll start writing a nice UI on top of it for easy maintenance and additional setup.
And before I finished this I just read about vyatta, not exactly sure all what it does but looks interesting.