I have a billion dollar idea: Start a grocery store. Seriously. When you have enough money start another. Keep going until you have thousands. It can't fail.<p>Another billion dollar idea: Start selling well designed Scandinavian furniture really cheap. Build a few megastores around the world, and make sure to squeeze your suppliers to keep prices down.<p>These two amazing ideas made Sam Walton and Ingvar Kamprad billionaires. Execution you say? Nah, these ideas are so obviously amazing that they've probably spent most of their time in business fending off blonde playmates while drinking martinis at the beach.