The following defence is known as the Falkbeer Counter-Gambit, after its author:

WHITE.BLACK.
1.P to K 41.P to K 4
2.P to K B 42.P to Q 4
3.K P takes P...

Not 3. B P takes P, because of 3. ... Q to R 5: ch., which would give Black a winning game.

...3.P to K 5

Black gives up a pawn for the attack, and a spirited game. It would be disadvantageous for Black to play 3. ... Q takes P, because White would then develop his pieces quicker, which it is the object of Black's counter-gambit to prevent.

4.B to Kt 5: ch.4.P to B 3

Both White's and Black's moves are the best available.

5.P takes P5.P takes P

Black takes with the pawn in order to maintain the attack, for which he gave up a pawn.