[s]ketchup

I just downloaded it a few days ago. There's a project going on at cherubforums, trying to simulate the whole thing in sketchup. I found it quite fiddly at first , but it's fun when you know how =]. ( If you're wondering , I didn't do the model above).
It is a kind of stress releiver , just messing about and creating random shapes. If you want to have a go it's here.
People actually use it for official jobs , and loads of buildings have been designed with it. I'd definitely use it if architecture ever came up as a problem in my life

piccurs: