http://www.hetemeel.com/hahaform.php
It's the famous Ha Ha guy. Originally from an old advertisement for Forbes Dry Insoluble Plates (a type of photographic plate), he was originally Photoshopped to say "Ha! Ha! I'm using the Intenet!" instead of "Ha! Ha! I'm using Forbes' Dry Insoluble Plates!". Now there's at least 2 forms I know of that let you add your own text. This is one of them. The other is at:
http://memegenerator.net/HA-HA-Guy