50 Best Websites 2010

We wouldn't recommend checking out Kongregate from work. The site's massive collection of online games will kill most of your day. Plus, the site's point system — letting users "level up" and earn achievements for in-game accomplishments as well as interacting with the community around the site — gives incentive to keep returning. Game designers have reason to participate, too, with monthly prizes for the best-rated games. (See the Kongregate mobile app.)