Fly Fishing Patents
My newest and most cool time waster has to be the new Google Patent Search. Basically you can type anything into it and see the actual diagrams and documents for the patent. Here is a link to the 1915 patent by Paul A. Haberl and Edger F. Warren for an improved, pear shaped, fly rod tip.
Update: It seems that the folks over at Namethatfly.org found this as well. Visit their blog to see more great fly fishing patent diagrams.