hmm, i saw this on tv a couple of days ago... i think they were trying to advertise againt it though!!!
get a pint pot, put a smirnoff ice in it, get three other alcopops and open them, very very quickly put them upside down in the glass with the necks in the glass, they should balance and not overflow the glass... add a couple of straws, and each tim you drink, the glas gets filled up again by the non empty bottles,
it sounds like fun, as depending on which straw you drink from, depends on which bottle empties in to the glass, and changes the flavor!!