There is $1.1 billion waiting for the 1.1 million people who didn't file their tax returns in 2007, according to the IRS. Before you get too excited, keep in mind that you need to file it by tax day, which is on April 18 this year. By law, you're generally given a three-year window to file your tax return, and if you don't collect your tax refund, it goes straight to the US Treasury. The IRS also mentioned that many of those who failed to file could be low-income workers who did not claim the Earned Income Tax Credit.
You might want to get going on this, because half of the 2007 refunds are estimated to be worth more than $640.