Idiomatic Polish

I think this forum calls for a thread with Polish idioms, as a lot of what passes as slang here is simply everyday colloquial way of speaking.
So, for a good start, just off the top of my head:

stawiać się komuś - to oppose somebody; act arrogantly

rozgrzebać robotę - (exactly what I'm at right now) - to start doing something and not be able to finish; robota jest rozgrzebana

zabierać się do czegoś jak pies do jeża - as above... try to get around to something, with lots of reluctance :)

iść pić na sępa - to get drunk on somebody else's expense (literal expense, money) :D

patrzyć się jak wół na malowane wrota - to stare at something/someone with dumb expression and without any comprehension :)

also:puścić pawia-to puke
walnać orła-to trip on something,fall

or Wyciąć orła

I think we both are familiar with the same joke :D

Spity jak bela = drunk as a skunk

Taki kram, taki sam! = As the master, so his servant.

I think you meant "jaki pan, taki kram" :)
but that's not colloquial speach, it's rather one of those sayings that are sometimes used (it's not a proverb, I think, but close to one).
some euphemisms for the verb "umrzeć" ("to die")
przekręcić się (to turn around, roll over)
kopnąć w kalendarz (to kick [in] the calendar)
wyjechać nogami do przodu (to leave with the legs forwards - in a hospital the nurses are usually superstitious, so when they transport you to the operation room, they almost always position the bed on wheels with your head in the direction of the movement, while transporting a body of a deceased the legs are in the direction of the movement)

Krzysztof,

You're right, of course! I thought I'd misquoted, but I wasn't sure. I meant more idiomatic expressions such as the type you've described.

pójść do piachu (go into the sand?) = to die
wąchać kwiatki od spodu (to sniff at the flowers from below) = be dead
dębowa jesionka (oak overcoat) = coffin