Think FedEx's spoofy Super Bowl ad played like a deleted scene from Cast Away? No wonder. In the spot, a Tom Hanks doppelganger (left) returns an unopened package from his island exile only to learn it contains a cell phone, GPS locator, water purifier, fishing rod, and vegetable seeds. Turns out a similar joke appears on the Cast Away DVD, with director Robert Zemeckis riffing that the mystery mail held ''a solar-powered, waterproof satellite cell phone.'' FedEx advertising director Steve Pacheco says he wanted to flesh out Zemeckis' punchline and nod to the 2000 blockbuster. ''We still can't do our jobs without people asking us what was in that box.''