The only NYC street gambling scam I was around to see, in 1989 and probably for a couple of years following, was the three cups thing.
I specifically remember watching it around Broadway and 4th Street, or somewhere in that area near Tower Records. Seeing it for the first time, I was as fascinated as anyone, and though I fortunately never felt suckered into playing, I watched as closely as I could, convinced that I, DR ChasSmith, should be able to follow and keep track of the damned thing. And of course I couldn’t.