Check out these awesome servers:

(Taken from Sky Gaming Organization)
========== HOW TO PLAY ==========

My Bind Config

bind f1 "up"
bind f2 "health"
bind f3 "haste"
bind f4 "laser"
bind f5 "respawn"
bind f6 "saferespawn"
bind f7 "tank"
bind f8 "witch"

Type /cost in chat to see item prices!

HOW DO I BIND A KEY?
Options -> Multiplayer Options -> Enable Developer Console.
Press the ~ key to pull down console and type the commands posted above. You can replace f1 through f8 with your own key binds, such as bind b "up"

======== DONATION BENEFITS =======

1. Reserve Slot (No more waiting!)
2. Ping Protection (No ping kicks!)
3. Kick Protection (No more idle kicks! Sends you to spectator!)
4. Entry for drawing of copy of Borderlands (April Only!)

Drawing will take place April 15th

========== OUR SERVERS ==========


- Sky-Gaming.Org - 20vs - 1 (75.102.38.23:27115)

- Sky-Gaming.Org - 20vs - 2 (69.90.119.145:27018)

- Sky-Gaming.Org - 20vs - 3 (69.28.221.172:27015)

- Sky-Gaming.Org - COOP Realism - 4 (174.142.98.77:37015)

- Sky-Gaming.Org - 20vs - 7 (75.102.38.24:27115)

- Sky-Gaming.Org - 20vs - 8 (174.34.135.190:27050)

- Sky-Gaming.Org - 24vs - 9 (174.34.131.36:27050)

- Sky-Gaming.Org - 20vs Community Maps - 10 (72.51.60.10:27015)

Join their group to see their servers in game.