X-Men: The Official Game (Xbox 360)

Bonus Iceman Danger Room level:
Press Right, Right, Left, Left, Down, Up, Down, Up, Start at the Cerebro Files menu.

Bonus Nightcrawler Danger Room level:
Press Up, Up, Down, Down, Left, Right, Left, Right, Start at the Cerebro Files menu.

Bonus Wolverine Danger Room level:
Press Down, Down, Up, Up, Right, Left, Right Left, Start at the Cerebro Files menu.