Method of swinging on a swing
United States Patent: 6,368,227. If you think the US Patent Office is doing any kind of due diligence researching patent applications, this will change your mind. I'd put this one on par with the Amazon "Single-click" patent or the British Telecom "hyperlink" patent. (via MetaFilter)
This patent was filed by a 7 year old boy from Minnesota named Steven Olson, according to the August 2002 edition of Harper's. Incidentally, the patent was awarded on April 9, 2002.