NeoTokyo is a mod for Sorce that just released less than a month ago. You can think of it as CS:S in Japan. The game centers around retrival of the Ghost (the flag) an android head/torso. When in possesion of the Ghost you can see enemy positions and call them out to your team as you head to the capture point. There are three classes:
Recon: Fast moving, light armor, long cloak, nightvision and a long jump that allows you to access places i the map other classes can't.
Assault: Moderate speed with sprint, moderate armor, short cloak and motion vision.
Support: Slow moving wtihout sprint, heavy armor, no cloak and thermal vision.
Cloaking, vision modes and the ability to lean set this apart from CS:S. The maps are beautifuly detailed and well lighted. If you want more info you can check out:
NeoTokyo HQ