4.0 of this wonderfully easy to use computer aided design program was
released recently. It features zero-learning curve and most
importantly - a Ruby API!
Animation is without keyframes and is wonderful. Checkout this clip I
made, from scratch, in under 15 minutes (I swear).
http://fivis.net/dropbox/AwesomerCad.mov

get it from http://www.sketchup.com/
-- 
</michael fivis>