For a while, I’ve wished I could get an itemized (or at least categorized) receipt from the IRS detailing where my various Federal (and state, though that wouldn’t be from the IRS) taxes go. It wouldn’t have to be incredibly detailed (e.g. $0.000013 of your taxes go to Private Snuffy’s food on June 12, 2011), but provide a reasonable breakdown.
Evidently the White House has had such a utility?since around the time of his State of the Union address. Nifty.