Queens Gambit Declined (Trap#1)

1. d4 d5
2. c4 e6
3. Nc3 Nf6
4. Bg5 Nd7
5. cxd5 exd5!
6. Nxd5 (White thinks they've won a pawn ... )
.. Nxd5 (This will win a piece for Black)
7. Bxd8 Bb4+
8. Qd2 (this is the only move ... )
.. Bxd2
9. Kxd2 Kxd8 & Black should have comfortable game with the extra piece.