Let's face it, the Schoolhouse Rock version of how a bill becomes a law is a gross oversimplification. In reality there are lobbyists and amendments, CBO scores and committees, and the ever-present threat of a filibuster. This graphic above, which you can see full size here, shows how a bill actually becomes a law.
This was just one of the winners in the Sunlight Foundation's recent Design for America contest. There's also an excellent guide to the Senate rules, and a brilliant, user-friendly redesign of the IRS website. You can see all the winners here.