I'm starting to work on a new game. My ultimate goal is to have a bunch of (hopefully) procedurally generated motored mobiles that race. I want to create a 3d environment where you can walk around, place bets on the mobiles and watch the races from a viewing area. It's really ambitious for me, so I'm going to try and just make smaller pieces of it. Eventually I may get enough experience making the pieces that I can make the game as I envision it, but until then I'm just going to kinda prototype it in smaller modular games. First, I'm using Unity's physics stuff to make the mobiles. I'm not familiar with hinge-joints and motors, but I'll get there by just trying to make some of these.

Here's what I've managed this morning:
https://edge.vncdn.co/vine/videos/ACCA86E6351121504768192618496_2aae047cdaf.0.2.11528573440603617092.mp4