Which websites offer free games?

It really depends on what you are looking for:

There are several categories of "Free Games" out there:

a) Online Games aka Flash Games (Games you play on a specific website without a download option) - Usually short games for a a couple of hours to play: Try 247PlayGames.

b) So called "Browser Games" - Online too, played in a browser like the mentioned Flash Games, but usually MMO games (Massive Multiplayer) try bigpoint or if you want 247playgames has a good selection of MMO's as well.

c) Downloadable Free Games - There are several publishers for free downloadable games out there - try bigfishgames - however these are demos...

Check out the related links below.