So usually I'm not an April Fools day fan, mostly because everyone thinks they are a damn comedian.
Having said that, there can be great pranks today, so let's here some of the better ones you have been either end of.
For me, it was 2 years ago. I had gotten tickets to the Final Four in New Orleans and April 1st was a day with no game, so I was with some friends having fun on Bourbon St. I got an email saying my brother had tagged me in a photo on facebook. I got on and saw it was a sonogram. Not really thinking about what day it was I called to congratulate him. It went straight to voice mail, and I proceeded to start buying people drinks and cigars to celebrate. He didn't call me back until about 3 hours later to inform me it was just an April Fools joke. Asshat cost me $150. Flash forward to today when his wife is actually due next week, if he calls me today...
Also, I feel sorry for the kids who waited until today to write research papers, they rely so much on Wikipedia, they will end up with some effed up info!