We happened to be in Melbourne during the Commonwealth Games. Not terribly exciting, but there were some interesting 'cultural' events on at the same time: There was one fish for every Commonwealth country down the Yarra (and two for Australia). At night they spurted water.
The best thing, though, was this: a large inflatable tent by the sea:
Because the plastic it was made out of was translucent, it produced all kinds of strange lighting effects inside: