You could also download some cracked .exe's
They are legal to use because all it does is get rid of the need for the CD. You can get one at gamecopyworld.com
Mods, if this is against the rules, then please tell me. But its not pirating or anything.
Actually, the use of cracked EXE's even with legally purchased games is still a bit of a grey area. As much as DRM sucks, it's especially blurry if you're using it to remove that DRM (requiring a CD to be in the drive is one of the earliest forms of DRM by the way, before some halfwit decided it'd be a great idea to actually write a program that would screw up games for both honest and dishonest gamers).
I wouldn't recommend to someone to do it, but if they came up with it on their own anyway then it's their choice.