Prague Spring: Held between May and June, it is the most famous classical music festival in the country. Venue - Opera House.
Rague Folklore Days, Advent and Christmas Music: An amazing Christmas time music festival also held in the opera house.
Festival spisovatela Praha (Prague Writers' Festival): Held in May or June, Czech and international literati gathers in to read extracts from their latest work.
United Islands of Prague: Held in June at the Vltava riverfront. Local and Global musicians perform here.
St Nicholas's Eve: Held on 5th of december around Charles Bridge & Staromestske Namesti, Stare Maesto, Prague 1. Men on this occassion wear frocks, drink beer and wander on streets.
Paleni Carodejnic (Witches' Night): It's a halloween bonfire night celebrated on 30th April.
Off the Beaten Path
If you want to explore the real drinking culture of Prague try the Underground Bar Crawl, for 500 CZK you'll get to visit many places you'd never otherwise see and have a few drinks in and around them and you get a free t-shirt too!