I believe it's F5 for screenshots in CS:S, should save to the Screenshot folder in CSTRIKE.
If you Pressed the screenshot button, go into paint and copy it.
Skype
___Games___
Paper Toss
Glow Hockey
Bouncedown
Traffic Rush
Run
Those are free/cheap apps, if you're wanting to spend money, get COD Zombies (Theres a lite Verison, so try it out!), GTA:CTW