NBA Jam  

Power-up Dunks 
get to the "tonight's match up" screen and start rotating the control pad 
clockwise until the tip off and hit button B 13 times before the faces 
disappear. This tip also works on the Sega Megadrive. 
Power-up Turbo 
tap button A 13 times then hold Y, A, and B buttons until the court appears. On 
the Megadrive, hit all three buttons seven times and then hold them all until 
the court appears. 
Juice Mode 
tap button A 13 times then hold buttons B and X until the court appears. On the 
Megadrive, tap any button 13 times then hold buttons B and C until the court 
appears.