The new version of Blogger, now out of beta, definitely counts as Cool Stuff. I just finished doing a few more blog tweaks here and there, nothing real major, just a little light housekeeping and decorating. It's really nifty how easy it is to edite the format of the blog.
If you're on Blogger and you've been hesitant to change over to the new version --- don't be. The whole process was relatively painless, and well worth it.