This site is an excellent time waster. Although it is obviously a joke patent, my curent favorite is the "User-operated amusement apparatus for kicking the user's buttocks". I would love to wallpaper my house with images from the patent database. I make ample use of the Quick Search field at the top of the site -- there are a lot of boring patents for chemicals and machinery, but it is worth it to browse through and find the hilarious and/or unusual ones. Note: if you use the right search terms, this is not hard.