You've probably heard a far bit about the budget jostling on Capitol Hill recently. Now I imagine most of you don't hang out in bars where C-SPAN is on round the clock, so you may not be totally up on all the ins and outs, but there's a very real chance that by the close of buisness March 4th, the Federal Government will be operating without a budget.
To grossly oversimplify the issue, the Federal Government authorizes and appropriates funds on a yearly budget. Once that budget runs out at the end of the Fiscal Year (Sept 30), Congress and the President can approve a temporary extension, or Continuing Resolution (CR). This is what the Government has been operating under since October, and the current one runs out March 4th. On that day, thanks to Art. I, Section 9 of the US Constitution (look it up yoursefl!) and the Anti-deficiency Act, it is now illegal for the Federal Government to pay its workers, outside of essential folks. The Congressional Research Service recently wrote an excellent report (.pdf) if you're a government affairs junky.