It's the quintessential teenage fantasy -- join a rock band, become famous, make a lot of money. Throw in a tragic plane crash and a troup of witty European actors and you have the makings of experimental theater RIPE for the Walker Art Center's annual "Out There" festival. Tonight marks the North American debut for the English-German ensemble, called Gob Squad. Their name refers to a type of schooling fish-- Gob-- that cares for its ailing members. At least that's what the performers say, prefering to ignore the other meaning's of the word which are British slang for both mouth and spit. The Gob Squad's play "Safe", opening at the Southern Theater, has been touring Europe for the past two years. The troup's Simon Will and Sean Patten say "Safe" is part theater, part plane disaster and part rock concert.