It's soo sweet, it's a 3D modelling program where you can make whatever you want, and it's free from: http://sketchup.google.com/
I've built my super sick box jam setup in .. half an hour.
Everyone should download it, you can make your dream setup, rails, jumps, 7/8 pipe, crecent rench, sex toy, whatever. Yeah, if you download it use the self paced tutorial under help and then post some pictures of whatever the hell you make. There's some more tutorials which are really helpful on the website.