Here are some cheats and tips for the game X-Men: The Official Game.
Bonus Iceman Danger Room level:
Press Right(2), Left(2), Down, Up, Down, Up, Start at the Cerebro Files
menu.
Bonus Nightcrawler Danger Room level:
Press Up(2), Down(2), Left, Right, Left, Right, Start at the Cerebro
Files menu.
Bonus Wolverine Danger Room level:
Press Down(2), Up(2), Right, Left, Right Left, Start at the Cerebro
Files menu.