I took a trip to Prague in September to celebrate the completion of graduate school.  The best feature of the city is its old world architecture.  The city went relatively unscathed during WWII and is one the few European cities that has maintained the majority of its buildings.  Prague has been dubbed the city of 100 spires.  The baroque style of architecture is prevalent throughout the city, however there are influences of cubist and gothic architecture that will transpose a visitor into many different eras of time.

I would recommend venturing to the outer part of the city to see examples of old communist housing projects.  The people in these areas were very inviting and is where I experienced the best of the Czech culture.  I would also recommend catching a local soccer and/or hockey game.