FIBonacci sequence

GolfScript (18 chars)

~]:^,,{^>3<~-+}?2+

The key to keeping this short is ? (find).

J, 30 23

(2+0 i.~2&}.=[:}:}:+}.)

Golfscript, 31 28 26 25 23

~]-1%~1{)\3$3$-=}do])\;