Rejs (The Cruise) is a 1970 movie from Polish director Marek Piwowski that gained cult status in Poland for its metaphoric treatment of Polish society. Two freeloaders get on a cruise ship on the Vistula river, pretending to be "officials". They are granted a position as entertaining officials, and mix with the holidaymakers, involving them into a very communist decision process concerning who should get involved in what activities. The movie is a satire of the whole communist way of life in Poland, when every aspect of life had to obey to the party's values. It was quite unsettling for me to see that movie as a non-Pole, as many details escaped me (I also was the only one not laughing my ass off). I had the opportunity to talk about it with Polish friends and watched it several times again (it is a short film at 65min). The humour is subtle and metaphoric, as everything revolves around "the captain", who is barely seen in the movie, but those presence is overwhelming.
Stuff of legend: a poem is read but the official is asleep and hasn't heard it. He is then disserting with the other passengers about its true meaning, turning it upside-down.

Although not a funny movie per se, it's a great way to discover Polish art and the subtleties of Polish humour under communism.