I once put a list of free games together on another forum. It's in german, and divided into 3 posts (1st post is freeware, second one free-to-play and the last one fangames, special promotions, browsergames and indie devs who give their games away for free (or at least some of them)), and each one is sorted by genre; also links to sites with additional free games. Haven't updated it in a long while, but might be worth a look for all those interested:
Thats a pretty fine list. Maybe you should update it and make a thread here on VGC. Imo it would make a good thread for here if you kept it up to date etc.