Repouche(re-poush-ay) is saying you saw it\did it\liked it first. Like dibs, or shotgun, except it means you already knew that, or did that, or liked it, etc. first. It means you are the first.
Frank Hardy: "I got to level 90 on MW3 yesterday."
Joe Hardy: "Repouche."
Shawn: "Gus, they are giving away double drumsticks at KFC! Just GIVING them away!"