Pen cannon
I've made my own cannon... You take an iron ink cartridge, take the ink out (the best way is to heat the cartridge, not write with it all day long as I planned to do at first :D), put 2-3 match-tops in it, compress it all together wit a match, put the match in on the top, heat it on the spot were the match-tops are, and bang... If it comes out right it can make a sound of a small firecracker, and the match can fly out up to 5 meters... I tried putting cartboard in front of it and it went through... Also, I mounted the cartridge on a toy-car chasis so that it looks like the german 88mm AA-AT gun.
Croatian: Napravio sam svoj topić... Uzmeš željezni uložak od kemijske, izvadiš tintu (i to tako da zagrijavaš uložak, a ne da cijeli dan pišeš s njim što sam ja bio počeo), staviš 2-3 kresa šibice unutra, naguraš to unutra sa šibicom, staviš šibicu unutra do kuda ide, zagriješ na mjestu gdje su kresovi i bum... Ako dobro ispadne čuje se ko manja petarda, a šibica odleti i do 5 metara. Stavio sam karton ispred topića i šibica ga je probila. Stavio sam uložak na donji dio autića da izgleda kao poznati njemački 88mm top.