Mado's dondurma lays claim to the mantle of "hardest and densest ice cream in the world." Even more so than Middle Eastern ice cream, Turkish dondurma is bolstered with sahlep and mastic; filling my cone ($2) required two strong hands and an implement wielded like a long-handled chisel. And yet whether chiseled, sliced like doner kebab, or bitten off, it melts in the mouth, I can vouch.
Multiple locations in Turkey
At Grand Bazaar to Grand Central
Grand Central Terminal, Vanderbilt Hall, 87 East 42nd St. (at Park Ave.), Manhattan
(The 2013 event, perhaps a one-off, was held on May 14)