The Federal Election Commission says that already, 2,341 have filed with the FEC as congressional candidates. By contrast, in 2008 only 1,717 people did that; in 2006, only 1,588. See this story.

Candidates for Congress are not obligated to file with the FEC unless they either raise, or spend, as much as $5,000. Therefore, the actual number of congressional candidates is even higher. Also, filing has not closed in many states. Thanks to Political Wire for the link.