We've been in language school for over ten months now and one of the ways I survive is by looking for interesting Polish sayings. Some of which are quite similar to English idioms and some are quite different.
1.) Wyszłam za mąz (wy-shwam za monz)----it's a phrase used for a women getting married, used quite often, and literally translated it means "I am going out to get a husband." (there is a joke in there somewhere but I'm too afraid to attempt it)
2.) kropla w morzu----a drop in the sea
3.) masz ku ku na muniu---you are crazy in the head
4.) pierza twój mózg (pi-eza tf-oo-i moozg)---literally, clean out your brain, somewhat similar to "get your mind out of the gutter"
5.) Stara miłość nie rdzewieje (stara mi-wosh-ch nie rdzewieje)---Old love never rusts. Incidentally men, I don't recommend using this English translation, in a hallmark card to your wife, anytime soon. Don't ask how I know.