Put down those bouyancy motor plans for a minute and check out The Museum of Unworkable Devices
This museum is a celebration of fascinating devices that don't work. It houses diverse examples of the perverse genius of inventors who refused to let their thinking be intimidated by the laws of nature, remaining optimistic in the face of repeated failures. Watch and be amazed as we bring to life eccentric and even intricate perpetual motion machines that have remained steadfastly unmoving since their inception. Marvel at the ingenuity of the human mind, as it reinvents the square wheel in all of its possible variations.

Be sure to read the excellent article, "The Psychology of Perpetual Motion Machine Inventors". Send it to a creationist.