Melanie Weisner (born September 30, 1986) is an American professional poker player. She is also known by her PokerStars online screen name Callisto 5.
Born in Houston, Texas, Weisner studied vocal performance at New York University before pursuing poker full-time. She was introduced to poker when her brother had success playing online. She earned over $400,000 of online tournament winnings playing part-time during her study at NYU.
She has had several notable online tournament wins. On March 30, 2009, she took third out of 10,614 entrants for $40,000 in the Pokerstars Turbo Takedown, a tournament with an entry fee of frequent player points with a prize pool of $1,000,000. On May 16, 2010, she took second out of 8,896 entrants in Full Tilt Poker's Double Deuce 200k Guaranteed Tournament, for $24,000. On August 2, 2010, she took third in the Pokerstars Sunday $500 "500k Guaranteed" Tournament for $50,398. On November 18, 2012, she took fifth place in the same tournament for $20,034. On December 30, 2012, she took fourth in the Pokerstars Sunday $100+ Rebuys tournament for $21.893. On April 7, 2013, she took third in the Pokerstars $215 Sunday Second Chance tournament for $26,933.