Nice games to record on the Mac?

I record gaming videos for youtube I'm only doing Minecraft and I don't know what other games to download that's free. Could you recommend games I can play thats free? I don't usually play games like Dota, LOL

Warsow - Futuristic shooter with a nice looking cartoon/Borderlands look. Difficult to play online since it's pretty competitive. Free.

Xonotic - Futuristic shooter with very high end graphics. Free but also has a very small community.

Osu (Mac beta) - A music game where you use your mouse to tap and slide things. Free but the majority of songs are Asian pop but there's a bit of everything from metal to techno.