Knicks vs. Celtics Game 6 Ticket Sells For $20k

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Folks are dropping serious coin to be at Game 6 of the New York Knicks' series against the Boston Celtics -- TMZ Sports is told one fan paid a whopping $20,000 for one seat at Madison Square Garden for the huge playoff matchup!!

Our friends at popular ticket platform SeatGeek gave us an inside look at the demand for Friday's contest ... and despite everything going on in the Big Apple, it's clear what's at the top of everyone's list.

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"The anticipation for Game Six at Madison Square Garden is at an all-time high with demand reaching record levels, making it the most sought-after ticket in New York right now,"…