Blackjack
Ungar's genius-level IQ and eidetic memory contributed to his blackjack abilities, which were so sharp that he was frequently banned from playing in casinos; he was eventually unable to play blackjack in Las Vegas or anywhere else.
In 1977 he was bet $100,000 by Bob Stupak, an owner and designer of casinos, that he could not count down a six-deck shoe and determine what the final card in the shoe was. Ungar won the bet.
Ungar was fined in 1982 by the New Jersey Gaming Commission for allegedly cheating while playing blackjack in an Atlantic City casino. The casino said that Ungar "capped" a bet (put extra chips on a winning hand after it was over to be paid out more), something he vehemently denied.
The fine for this offense was $500 however paying it would also force Ungar to admit that he cheated the game. Ungar believed that his memory and card counting ability were natural skills and thus he didn't need to cap bets or partake in any form of blackjack cheating. Ungar fought the case in court and won, avoiding the $500 fine. However, he did pay an estimated $50,000 in legal and travel expenses. In his biography, Ungar noted he was so exhausted from travel and court proceedings that he was not able to successfully defend his WSOP main event title.
In 1997, a near-broke Ungar convinced the management at the Lady Luck to let him play single deck blackjack. Being a known card counter, they agreed on the condition that his betting would have a high and low limit, thus neutralizing Ungar's card counting ability. Ungar continued to play at the Lady Luck for six months. Ungar built his bankroll up to as much as $300,000 but eventually busted.
Read more about this topic: Stu Ungar