In Puerto Rico and the Dominican Republic, and (usually) in New York, it's called a quenepa (keh-Nay-pah; pint, $3); elsewhere, it goes by mamoncillo and many other names. The quenepa is an ovoid fruit akin to the lychee, and eaten much the same way: Peel off the thin, green rind, pop the pulpy mass into your mouth — it tastes like a sweet lime with a hint of banana — and work it around until all that remains is the (relatively large) pit. For your efforts, expect a small dose of flavorsome juice but very little fruit, though if you're ambitious, reportedly the pits can be roasted like sunflower seeds.
Previously: You probably wouldn't think twice about a splash of lime juice on your mango, but give a nod to the salt and chili powder, too; sweet-sour-salty-spicy is uncommonly tasty.
Red Hook Ball Fields
Near Clinton and Bay Sts., Red Hook, Brooklyn
Saturday and Sunday, May through October