Memento Park – or Szoborpark (“Statue Park”), is a depository for communist-era public statues.
Located on the very fringes of Budapest, you should allocate quite a bit of travelling time to getting there and back, or catch the once-a-day direct bus that leaves at 11:00 from Deák Ferenc Metro station and goes back to the city at 13:00 (or just drive).
Lots of people get a kick out of seeing these monumental statues in their new, “harmless” environment, but given nice enough weather, the park is also a good spot to get away from the city’s concrete for a bit.
Just outside the main entrance, there’s a barrack where they sometimes have temporary exhibits as well as some permanent information on the 1956 revolution and the 1989-90 change into democracy.
Definitely check it out, as there’s also a movie theater inside, showing a subtitled documentary called “Life of the Agent.” It’s a compilation of actual black-and-white training videos filmed by and for the communist secret police, teaching you how to conduct proper house searches, how to follow someone unnoticed, how to enlist someone as an informant, and other similar skills. You can also buy the movie on DVD at the ticket office, and it’s awesome.