The Kieninger Trap, seen below, is probably the most commonly played trap in the Budapest Gambit (1.d4 Nf6 2.c4 e5). It is named for Georg Kieninger, who first sprang it in 1925 in an offhand game against Godai in Vienna. (Shouldn't Kieninger have been playing the Vienna Game instead?) Some Budapest detractors say that this trap (which appears 14 times in ChessBase's Big database), is the only reason to play the Budapest. Not true! There's also 3.d5 Bc5 4.Bg5? Ne4! 5.Bxd8?? Bxf2# Arnold-Hanauer, U.S. Open 1936. In all seriousness, the Budapest is not that bad. IM Tim Taylor does a good job demonstrating its virtues in his 2009 book on the opening.