From StarWars.com:
Actors Samuel L. Jackson, Liam Neeson, and Ewan McGregor, as well as their Jedi alter-egos, along with Star Wars creator George Lucas and stunt coordinator/swordmaster Nick Gillard have signed a Master Replicas Luke Skywalker lightsaber that will be auctioned, with all proceeds being donated to Northern Ireland Children's Hospice. Also being auctioned off is a signed Jumper poster, autographed by Hayden Christensen. You can find out more at the above link.