Douban

I love douban.com! It's a Chinese site, so if you can't speak Chinese it's not really worth visiting, but if you can, check it out! There's tons of info on movies, books (most listed under Chinese & English names), etc. and users' reviews on these topics are really helpful. The coolest part of the site is the 同城 (Same city) where you can find events in the city where you live. Bands (even the little-known ones) also have Douban pages where you can check out their upcoming concerts and listen to songs. The site is huge, constantly growing, and has tons to explore!