This has recently become one of my favorite lunch spots. Its a small place with only 3 or 4 tables and a few shelves of Polish (Ukrainian?) groceries. They do sell frozen pierogis but stop in and try them fresh - you'll fantasize about them.
They have a small lunch menu - basically several types of pierogis, sausage, and various substances covered in cabbage. Not so hot on the last two but I've had most of the kinds of pierogis they sell and they are all great. Try the farmers cheese and potato ones fried with sour cream and bacon on them!
Also - Last time I was there they were also selling bits of a 5 lb block of sunflower halva. Its a desertish thing that looks like... well it looks like you'd find it on a barn floor but it tastes wonderful. Definitely give that a try if your looking for something new.