Bryndza is an Eastern European cheese from sheep's milk. Like many things of Eastern European provenance, if one hasn't been brought up with them, you pretty much have to take the initiative to find them (or imitations thereof) in ethnic areas of town.
I can't recall ever trying this, but I did eat lots of Oscypki (smoked sheep cheese popular in southern Poland) on my visit there last summer ... washed down by lots of good, cold Warka.
The process for making bryndza is similar to that for making quark. The sheep's milk is strained through linen into small wooden casks named putina or, traditionally, into a leather truckle made from the skin or stomach of a cow, sheep or buffalo, called a burduf in Romanian. The putina are often made from spruce or fir wood.
http://en.wikipedia.org/wiki/Bryndza