At least this cute little one by Matt Armstrong (monsterbrick). My favorites for sure are Oscar the Grouch and Elmo’s little clam head, but Cookie Monster comes in a close.
Why in the world am I not camped outside Matt’s house waiting for the next great creation?
This SURE looks like a simplified version of Mike Crowley’s (Count Blockula) Seasame Street from several years ago.
Here is the original if you’ve not seen it:
http://www.flickr.com/photos/countblockula/sets/72057594064701049/