Over 125, according to this recent blog post.
Scribblenauts Guide is one of our affiliates and has decided to take on the unique task of categorizing and organizing information and media surrounding Scribblenauts. Whereas I have the luxury to simply report news and write various opinion pieces, these guys have to record every object...all TENS OF THOUSANDS of them.
Thankfully it's a community effort. If you've never heard of Wet Paint before you can think of it at as Wikipedia. Anyone can sign up, do some edits, add some media, whatever.
So head on over there and see if you can help them break 200. Then 300. Then 400. Then...well...you get the idea. Better get crackin'!