Michael Floyd is just awesome. He is really great about showing you how to make some really amazing sculptures out of just like 2 balloons or so. The balloon below requires just 2 balloons to make!
He has a Stegosaurus tutorial on YouTube that is really fun to make. He does a really great job instructing and goes at a very considerate learning pace.
Link to his tutorial here, http://www.youtube.com/watch?v=bEHj9aYcbws.
My replication below.