This new ad from Huggies is hilarious. Not only is it specifically aimed at dads (how long did THAT take?!), but you can totally imagine it happening to you. You're at your boss' house for a work party and slip into a quiet room to change a diaper, then ... ARG!
The kid looks so pleased with himself!
And just to prove to any non-parents that this does indeed happen, here's an older blog from Marko Polo with golden evidence.