Practice Courts:
At any screen before game play begins, type "Playground" to play at the night court or the daytime practice court.

Power Dunks:
When in the main menu screen, type "redrover" in all lower-case. At this time you should hear a noise.

Michael Jordan:
Defeat Michael Jordan one on one in superstar mode to unlock him on the roster.

Isaiah Thomas:
Get fifteen steals in a game in superstar mode to unlock him on the roster.

Easy Scoring:
Pump fake to get your opponent to jump. Now just go for a dunk or any other pretty looking move.

Thanks to Revolution reader Monzur Morshed!