Building a Mo-ped. Is it possible?

[Riskwise]

I have tons of time this summer before college, and a friend and I have decided we want to invest all summer trying to build a mo-ped, like either adding some weed wacker motor to a bicycle, or going all out and buying some kit off of the internet to make a street legal, safer, one. I am posting to see if ANYONE has ANY knowledge about the topic what so ever. I have no idea what im doing and have no idea what to even "google" to find some quality advice on how much it will cost, where i can get a kid, if they even exist, and whether I will even be capable of doing this. Any help is apprieciated.