Play the Marshall gambit.

One of Black's more aggressive alternatives to fight the Ruy Lopez is the Marshall Attack: after 3...a6 4.Ba4 Nf6 5.O-O Be7 6.Re1 b5 7.Bb3 O-O 8.c3 Black plays 8...d5, sacrificing a pawn with 9.exd5 Nxd5 10.Nxe5 Nxe5 11.Rxe5 being the main line. The Marshall Attack was introduced by Frank Marshall in a famous game against Capablanca in 1918. According to legend, Marshall saved this prepared innovation for eight years before getting the chance to play it against Capablanca.Capablanca weathered the Black attack and won brilliantly. Improvements to Black's play were found (Marshall played 11...Nf6 instead of 11...c6) and the Marshall Attack was adopted by top players including Boris Spassky.