Sack In The Box

This level is easily one of the best I've seen. It has very good machinery and AWSOME emitter setups. He makes platforms fly into the air, do a flip, then land perfectly so you can walk over. He also does a few creative things with paint, including a machine that follows you around and drops paint on you.

You can do the same thing by changing how much the platform spins and then tweaking it until it lands perfectly at the place you want it to land.