Paul put in a request for the Siesta Gambit in the Ruy Lopez but I couldn’t find any decent YouTube videos (which I need otherwise I don’t know what to do in these highly tactical openings). So I’ve gone for something similar in the Italian Game which also involves black sacrificing a pawn with f5. Apparently the engine’s first reaction is that this is a blunder because of the reply Ng5 but this leads to some wild and wooly play.
Anyway, play will start with White to move after the moves 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. d3 f5!. I found two YouTube videos covering this opening, one where White declines the pawn and one where White accepts.