I made the balloon outlines thinner here but still haven't figured out how to curve the tails. Also, it's surprisingly frustrating trying to gauge size using the oval tool. I'd just use the rounded rectangle tool except that looks kind of lame. Now I know why Mad magazine always used rectangles.

edit: Oh, wait, I just realized that I finished this one before I read those comments on the last one, so this one technically incorporates NONE of your helpful suggestions and just sucks. The next one has thinner balloon lines. Maybe the one after that will have curved spouts too.