Here is one of the funniest pranks I've seen. It would make a great April Fools joke...but it could get you murdered. Not safe for work (language)...
For the second year in a row, Thad's friends planned a prank to make him think he won the lottery. They taped a previous night's lottery drawing and then bought a lottery ticket to match those winning numbers.
http://www.youtube.com/watch.php?v=pFMXfGvDRts