X-Men Legends/X-Mansion, Estate Grounds

You're back at the mansion, in the Estate Grounds, you can talk to several students, and to Jubilee as well. But before starting the next mission, there are some things to do (see below). When you're done, go to the subbasement, here you can talk to Toad if you want, but anyway head to the Danger Room. When you're done with it, go talk to Beast to do the Juggernaut Flashback. When you're done with the Flashback, head to the War Room to start the next mission.

Collectibles
1 Danger Room disc (Protect 202) (in the dormitories) For the rest, see below

Sentinel Flashback
Inside the mansion, first floor, find and talk to Nightcrawler 1 Danger Room disc (Defend 202) (in an alley near the beginning) Nothing Nothing 1 Comic Book (on a rooftop, get it before defeating all the sentinels, use Jean to reach with Flight, not available in the Xbox version apparently)
 * How to start
 * 7th Avenue
 * 8th Avenue
 * 9th Avenue
 * 10th Avenue

Juggernaut Flashback
1 Danger Room disc (Challenge Cyclops, by the stairs)
 * Collectibles