7. Lange Nacht der Museen

The Buzz -- Held in the winter and summer, these unique events see more than 100 museums and other cultural hubs stay open well past their normal bedtimes. Buses run throughout the "Long Night," shuttling visitors from gallery to gallery, museum to museum, until things finally close down at 2am. In addition to the regular array of exhibits (which are, of course, even more spectacular when viewed under the night sky), many institutions feature live performances, food and drink.