U.S. Patent No. 6368227
Covers the method of swinging on a swing. So if you are in the US and want to sit on a swing, get ready to pay royalties to 5 year old Steven Olson.
Doesn't come much as a surprise, given that someone patented fire and wheel.
I think i can apply for a patent on "A liquid chemical prepared by the complex atomic conjunction of molecular hydrogen and molecular oxygen, that supports and sustains the highly organized auto-cannibalizing system naturally emerging from conditions common on planetary bodies, and consisting of a population of replicators capable of mutation, around each set of which a homeostatic metabolizing organism, which actively helps reproduce and/or protect the replicator(s), has evolved and derivations thereof"
For more info on such patents and the flaws in the US patent system: IEEE Article on US patents
PS: How many patents does 6 year old Calvin have? His dad is a patent attorney.