Venturing into the neighborhood of Nivy, you'll find this large outdoor market full of fresh produce, cheap goods, and a few stands selling true Slovak street food.
For me, I come to this spot to get langoše (lahn-goesh). It's yeast dough stretched to a 10"-12"disc, and then deep-fried in oil. You can top it with garlic butter, or ketchup, or ketchup and cheese (like a pizza). Not the most healthy food, but definitely good for once-in-a-while.
The market itself is quite nice, as you can find very cheap (but low-quality) merchandise and the produce is well worth it, comprable to any decent farmer's market here in the US. I will forewarn any travelers though to watch your bags and pockets, as many gypsies do congregate here.