Well, several days ago, the bat posted about his experiences using Google sketchup to draw the Tomb of Horrors. I saw the post but quickly forget where I saw it. Thank you, reader Staples, for telling me where it was. By the way, it was here.
The crazy thing was that at least two other bloggers also posted about the Tomb of Horrors on that day, and unlike as often happens, it didn't seem that their posts were related thematically in any way--other than by topic. Mmmmmm.
Of course, the above is only one example of what can be done with Sketchup. Here is a castle. And here is something else. Actually, there are lots of them over here--you just have to spend a little time looking. I've not taken the time to play around with it, but from what I've gathered, it's fairy easy to learn, and, while not super-powerful, is powerful enough for any amateur or even semi-professional 3D mapping,