I thought the io9 article on a guy making weapons from stuff you can buy inside the gate was hilarious, from a projective weapon based on compressed gas cans to one based on a blow dryer.
And it's not just airports. Nearly all Federal Buildings have this silly charade at their doors, including one in downtown Sacramento that contains a US Post Office. A friend had a small pocket knife with him when we went into that building a few years ago. They made him check it at the door to be picked up later. It was so absurd that we seriously though about getting a PO Box there, mailing ourselves three or four huge Crocodile Dundee-sized hunting knives (maybe a Samurai sword too), go through the entire "check the 2-inch pocket knife" ordeal, pick up our knives and sword from the PO Box and then walk back to the security checkpoint from INSIDE the building with the knives and sword strapped on as we ask for the stupid little pocket knife back.