When I've got some friends on I will usually play on this steel mill no time or kill limit server, so you end up quiting a few hours later with 400+ kills. Incredible fun...but gets boring because sometimes hackers come in. Doesn't matter now that I have installed the patch I can't play there because it is a different version.
I also frequent BROS 24/7 Mesa and BROS 24/7 Mesa DX9 Day/Night server. (Woo big difference there H4yd3n.