It's always amusing when you can trap your opponent's queen. A primitive example of this, which any 1.e4 player will eventually have the thrill of playing, is 1.e4 d5 2.exd5 Qxd5 3.Nc3 Qc6?? 4.Bb5!, Rhine-Melko, Chicago 1972 (and countless thousands of other games). And who can forget the immortal 1.Nc3 d5 2.e3 e5 3.Qf3? (3.Qh5!? is actually a good move) e4 4.Qf4?? Bd6! trapping White's queen in the middle of the board?
A somewhat more sophisticated queen trap can arise in the Fajarowicz Variation of the Budapest Gambit. In that strange variation, Black sacrifices a pawn (1.d4 Nf6 2.c4 e5 3.dxe5), then plays the eccentric 3...Ne4!? (rather than the normal 3...Ng4), making no effort to regain the pawn and placing the knight in a vulnerable position. After 4.Nf3 (4.a3, 4.Nd2, and 4.Qc2 are also playable), Black can continue the provocation with the remarkable 4...b6!?, practically begging White to fork Black's rook and knight with 5.Qd5!? As the game below shows, there is a method to Black's madness. After 5...Bb7 (5...Bb4+!? is also possible) 6.Qxb7 Nc6!, White's queen is in trouble and threatened with capture after ...Nc5 or ...a6 and ...Ra7, although White could still get rook, bishop and pawn for it by taking Black's rook. Grandmaster Viktor Moskalenko suggests 7.Nd4!? Bb4+ (7...Nxd4? 8.Qxe4; 7...Nc5? 8.Nxc6) 8.Nc3 0-0!? (8...Nxc3 9.Nxc6) 9.a3! Nxc3 10.e3! "and good luck with the rest." The Fabulous Budapest Gambit, p. 216. He cautions that 4...b6 is advisable "only when playing blitz or on the Internet."
The natural 7.Qa6?? was a blunder. After 7...Bb4+! 8.Bd2 Nc5! 9.Qb5, White may have expected 9...a6?? 10.Qxb4, winning three pieces for the queen. Black dashed this hope by interpolating 9...Bxd2+! With just two pieces for the queen, White resigned two moves later. Another White misadventure in this line continued 7.Be3 a6 8.Nd4 Bb4+ 9.Kd1? Ra7! 10.Nxc6?? dxc6 CHECK! (woops) 11.Kc2 Rxb7 and White could have resigned in Heroiu-Otto, Hamburg 1997.
White can even aim for this trap with an extra tempo, e.g. 1.Nf3 d5 2.b3 c5 3.e4?! dxe4 4.Ne5, the Norfolk Gambit, which occurs 11 times in ChessBase's Big Database. It was advocated by the late Claude Bloodgood, who became one of the highest-rated players in the country while serving a life sentence for murdering his mother. He wrote books about three of his pet openings: the Norfolk Gambit, the Hartlaub Gambit (1.d4 e5? 2.dxe5 d6?), and Grob's Attack (1.g4).