OK, I've gone and gotten myself addicted to mamey batidos, which are milkshakes made with a kind of Carribean or Central American fruit. The milkshakes are not too sweet and have some almost chalky texture to them.
I've been getting them at Havana Chelsea (my favorite hole in the wall Cuban) and I recently tried one at a hole in the wall Mexican place on 9th Avenue and 38th street (Havana Chelsea's was better).
Any recommendations for other places to try? I'd prefer south of 59th Street.