This site has the best free games collection
Titles are from all genre like Action, Adventure, RPG, Strategy, and a whole lot more
Abandonia reloaded is IMO the best site to look for free games, this guys list only the most enjoyable games out there.
The site has a very clean interface that is a joy to navigate and the forum is well moderated with friendly and respectfull users. The games are also rated by the editors and are balanced out by the votes of the users. Reloaded is a good website with a good community. No, I don't work for them, I just really like the site.
Another good site to check out games (some are demos) is Indie Gamer . This site has a wide selection of games reviewed in his archvie. Indy Gamer is listed on my blogroll in the sidebar.