Where the DIYer goes, the kit maker soon follows. We recently spied these cool-looking kits from EnVision Labs and AntiGravity Research, both of which will allow you to build towering, multi-stage water rockets using special connectors. Watch for reviews on makezine.com.

But even without a kit, you probably already have everything you need (or can easily aquire it). Consult aircommandrockets.com for advanced hydrorocketry ideas