Heavily inspired by Lego Ninjago Airjitzu toys and Beyblade (all trademarks are the property of their respective owners).
The spinning top consists of 4 parts. The axis with the gear is compatible with the Lego Ninjago Airjitzu toys. The disk consists of two identical halves that allow you to insert up to 6 coins (5 Euro-cent) for more momentum. The bottom cone should fit tightly on the axis, but could also be screwed on with a M3x30 screw or you could just use glue.
Warning: If you put in some coins you might want to be careful near valuable furniture!
The launcher consists of a box with handle and lid and the starter strip.
As an arena we used a lid from a big pot, turned upside down and placed on a bowl for stability, but of course you can use whatever you want.
The gear was created with the library by GregFrost: http://www.thingiverse.com/thing:3575