Big plastic squeaky hammers inspired a contest that takes place in Porto for four years now. More than 200 proposals are on display until 16th July at an exhibition. These are the ones I sent. the first one is a Paper Toy and the second is a Flip Book. You can download the Paper Toy model an build the paper toy hammer. Pdf has all the instructions. It's very easy! http://www.mediafire.com/view/x46n9rgdaf2fxv1/MarteloPaperToy.pdf
The Flip Book hammer:
In this video you can watch the plastic hammer in action! The author of the video summarized the festival in a few lines: "This was one wild party in Porto, Portugal celebrating the city's patron saint, and we loved every minute of it. The tradition is to eat grilled sardines, drink Super Bock beer, and go around whacking each other with big plastic squeaky hammers. At midnight, they set off fireworks from a whole line of barges anchored in the Douro River-- the best display I've seen. Then the party goes on until 7 am (but not for us). Our apartment was right on the riverfront, so we're glad we brought earplugs for sleeping."