DEADLINE shows you mercilessly the remaining time until your deadline.

Download the lastest Version here.

View the sourcecode, it tells you how to compile it.
After that, run it with ./deadline 01012004, and it tells you the remaining time until new years eve *g*

I put it into my .xsession, and so it keeps telling me how much time I have left in this university. Pretty cool, huh?

OR, use it as an alarm clock. For example, you want to stand up on June, 13th 2003 at 1pm? Not a problem:
./deadline 130620031300 ; mpg123 "Guano Apes - Open Your Eyes.mp3"