Yeah some med schools have spring break. My friends and I are heading to Cancun so I guess it is the same culture as undergrad. In my experience, partying is more intense in med school, not that I didn't party in undergrad either (in fact I am really lucky I did not get cited for the parties in my ugrad apartment).
During first and second year, we get three weeks for christmas, and one week for spring break, either in late march or early april. Summer between first and second year is five weeks long. However, after finishing second year, all bets are off. No more summer, winter break is maybe one week, and no spring break. However, from what I hear you get lots of time off during 4th year for interviewing and doing optional away rotations. So all you have to do is survive the hell that is third year and you're home free.