Here’s a look at a variety of tools to bring your employees together in extracurricular activities:

Fantasy Sports: Tens of millions of people are already playing fantasy sports which let users draft a team of their favorite professional athletes and compete with each other and win and lose based on how those athletes perform. Yahoo Sports and CBSSports both offer web-based tools for managing your own private fantasy leagues for every major sport, so you can setup competition between employees. 

Sports Pools: If Fantasy Sports are a bit too involved (and you worry your employees will waste away too many work hours on them!), there are also plenty of options for running more traditional sports pools.  PoolHost lets you setup a traditional “pick ‘em” pool where players simply choose the winners of games – typically football.  The service can also power a Super Bowl squares pool, where players simply select numbers and win based on the score of the game at the end of each quarter of play.

Reality TV – If you’re looking for competition beyond sports, there are plenty of games to be played around popular TV shows.  Fun Office Pools lets you create pools around shows where someone gets voted off each week, like American Idol, Dancing With The Stars, and Survivor.  Fafarazzi offers a wide variety of games for entertainment lovers, both for reality TV shows and for things like drafting celebrities and earnings points based on which are getting the most publicity, what the site calls “Fantasy Celebrity Leagues.”

Inter-Office Competition – If you want to take the competition outside of your office, DareMyCompany is a site that looks to hookup different companies in a variety of activities.  The focus is competitive sports, but also allows for less athletic events like ping pong and even video games.  Once you’ve validated your company, you can post a challenge, inviting other businesses to compete against you in the activity of your choice.

In addition to using these tools to build rapport inside of your office, they can also be utilized for networking.  For example, you could organize leagues for other local businesses or industry peers.  Remember though, gambling on these games is technically illegal in most places, so it’s best to play either just for fun or for a favorite charity (at least I can say I told you!).