I studied there too.
-Eat and shop outside of Old Town Square
-Try the Smazeny Syr
-If you go their in late Nov.-Dec disregard the first comment and go to the Christmas markets and get drunk on alcoholic deliciousness.
-If you go to the astronomical clock take a video camera. Don't point it at the clock point it at the crowd of people staring at the clock and record how pissed and dissappointed they are that they spent 15 minutes waiting for the worst imitation of Disney's Its a small world ride.
