Well the first thing to waste your time has to be the baloon helicopter.
The helicopter
1.Get an old cd ,a baloon and some super glue.
2.First get the old cd and put super glue around the rim of the small hole in the middle of the cd.
3.Next get the baloonand stick the bit where you blow into on the super glue.
4.finally blow into the baloon and wait untill its full pinch the blow hole and let go!