In 1988 this gambit got its international name from The Elephant Gambit by Jensen, Purser and Pape. Shortly after publication of the book, the authors organized the Elephant Gambit World Tournament (correspondence) which was won by Ernst Rasmussen, an expert, from Washington State.
The opening itself dates back to the time of Staunton. Black ignores the attack on his e-Pawn and immediately tries to seize the initiative. While the resulting positions are quite sharp, it's generally considered unsound because if White plays accurately Black does not get sufficient compensation for his scarificed P. But, of course we all know that often White won't play accurately (at least at the level most of us play at) with the result that Black's chances are excellent; at least they are if he is a good tactician. If your tactics stink, I'd avoid it.
Just for fun, I tried it recently in a Blitz game which I played with zero knowledge of any analysis; the result was that I was left a P down but managed to draw anyway. Things quickly got a little too messy for my taste, but after Qs were traded things settled down; it wasn’t so bad if you don’t mind being a P down with no compensation.
Anon - Tartajubow
[Houdini 1.5 x64 (10s)]
[C40: Latvian Gambit]
1.e4 e5 2.Nf3 d5 3.exd5 e4 4.Qe2 Nf6 5.d3 Qxd5 [5...Be7 6.dxe4 0–0 7.Nc3 Re8 8.Bd2 b5 9.Qxb5 Na6 10.Nd4 Nxe4 11.Nxe4 Bf6 12.Ne6 fxe6 13.Nxf6+ gxf6 14.0–0–0 exd5 15.Bc3 c5 1–0 (15) Kotronias,V (2590)-Pandavos,P (2360) Peristeri 1993] 6.Nbd2 Be7N [6...Nc6 7.Nxe4 (7.dxe4 Qh5 8.Qb5 Bc5 9.Nb3 (9.e5 Nd7 10.e6 fxe6 11.Nb3 a6 12.Qc4 Be7 13.Be2 Nb6 14.Qe4 Qf5 15.Qxf5 exf5 16.0–0 0–0 17.Bf4 Nd5 18.Bc4 Be6 19.Bg5 Bf7 20.Rad1 Rad8 21.Bxe7 Ndxe7 22.Bxf7+ Kxf7 23.Ng5+ Kg8 Unzicker,W (2525)-Heuer,V (2200) Tallinn 1977 1–0 (39)) 9...Nxe4 10.Be3 Bb4+ 11.c3 Qxb5 12.Bxb5 Bd6 13.Na5 a6 14.Bxc6+ bxc6 15.Nxc6 Bd7 16.Na5 Rb8 17.Nc4 Be7 18.0–0–0 Be6 19.Na5 Bxa2 20.Nc6 Ra8 21.Rhe1 Bd6 Aveskulov,V (2532)-Kalinichev,A (2403) Tula 2008 1–0 (49)) 7...Be6 ½–½ (7) Seeman,T (2422)-Kalinitschew,A Tallinn 2006] 7.dxe4 Qc6 8.e5 Nd5 9.Nb3 0–0 10.c3 Bg4 [10...Rd8 11.h4=] 11.Qe4 f5?! [11...Qd7 12.Bc4 Nb6 13.Bd3± (13.Qxb7? Nxc4 14.Nbd4 c6 15.Qxd7 Nxd7–+) ] 12.exf6 [12.Qc4 Qd7 Black has to keep the Qs on if he has any hope of counterplay. 13.Be2±] 12...Nxf6 13.Qxc6 [13.Qxe7? Re8; 13.Bc4+! Kh8 14.Qe2] 13...Nxc6 [13...bxc6 14.Bc4+ Kh8 15.Ng5±] and the game was eventually drawn.
One of the leading exponents of the EG is Philip Corbin, an FM from Barbados. In the following game he uses it to defeat the much higher rated IM Tadej Sakelsek of Slovenia.