Humor.ws
Play hundreds of free arcade games @ humor.ws
http://www.humor.ws/

Free Online Games
Comprehensive online game collection with no signup process or complicated steps to get started...just a simple way to play for free! Classic Nintendo, action, adventure, arcade, sports and much more.
http://www.excessively.net

Free Flash Games
Extensive collection of free Flash games presented in a well-organized category structure. Available categories include action, puzzles, sports, strategy, shooting, arcade, adventure, and more.
http://www.gamecapacity.com

Free Online Games
Free online game portal in well-organized category structure. More than 18 categories with more than 3000 games. Website is updated everyday!
http://www.onlineflashgames.org