I got into it for a while over the summer (time is so short now that classes have started again... sigh), and I found out that if you have Photoshop, you can open the one file type they let you save as in the free version of Sketchup there, and then save it in any other format you like, which is nice. Maybe this doesn't seem as awesome to others as it does to me, but I was psyched that I was (if memory serves me correctly) getting the functionality of the full version for free
(of course, it's not totally free, but I had already bought PS for other purposes, so it effectively was, I like to think
).
I was planning on doing some animation with it sometime (probably with After Effects or something, which I'll get when I have more free time to putz around). I'll post my evil wizards castle when I get a chance.