Koh Phi Phi is very beautiful (tho we liked the area around Krabi better!), and very, very crazy! Night time activities on offer (during the 3 days we were here) included... multiple beach parties, a pirate night, Muay Thai boxing (there was actually a ring in one of the bars - beat up your friends for free drinks!), a wet T-shirt competition (highly cultural stuff!), fire dancing, fire limbo, fire rope jumping (in fact anything they could do with fire they did!).
During the days we explored the island a bit - all of the crowds were in the main 'town' and its beaches, the rest of the island was beautifully peaceful, and the beaches idyllic. We also explored away from the island by diving (for Tara - no whale sharks,but 4 turtles!) and a snorkelling and kayaking sunset tour (for Da, who picked a perfect sunset for it!).