How do you make a yo-yo that's not made out of cans, and its still easy?

I've seen instructable(s) on yo-yo(s) made out of cans, but is it possible to melt plastic/use rubber/use metal to make yo-yo(s) and its still easy and safe to make?

You can make a Yo-yo out of any matched pair of flattish round things joined by an axle. Use a hole saw to cut two discs of wood or thick plastic sheet and stick an axle between them. Bam! Yo-yo. Make a silicone mold of the appropriate shape, fill with resin, drill holes and fit an axle. Bam! Yo-yo. Get a couple of plastic or metal jar lids and connect them with an axle. Bam! Yo-yo.
The only trick is making sure the axle is perfectly centered.