Pretty classic sacrifice. Only works on Newbies...black is much better
something weird with two knights

My specialty is with the Italian Game so I can give you an in depth look at your line.
After 4.d3, black has four options
4...h6 5.0-0 d6 Re1 Na5 or g6
4...d5 5.exd5 Nxd5 6.0-0 Bc5 but this is a risky variation to play after 7.Bb5!
4...Be7 5.0-0 0-0 6.c3 d5 7.exd5 Nxd5 8.Bb5 f6!
If 9.Re1 Bg4! 10.Nbd2 a6 11.Bxc6 bxc6
If 9.h3 Qd6! 10.Nbd2 a6
Finally 4...Bc5
This transposes directly into the Italian Game. The particular variation is known as the Giuco Pianissimo normally reached by the move order:
1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.d3 Nf6
Theory continues 5.Nc3 d6 6.Bg5 h6 7.Bh4 with a positional game.
Now your opponent played a very poor move 5.Ng5 because it loses time and exchanges off white's developed pieces, notebly the light square bishop.
After 0-0 6.Nxf7 Rxf7 7.Bxf7 Kxf7 8.Bg5 d6! and white is losing positionally and materially. Two pieces almost always win against a rook. Anyway, White has only a bishop developed with no counterplay. Black should win in the endgame.
<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} -->
Well, I’ve actually seen this twice lately and just wanted to get opinions on it. Personally, I think it’s dubious but my knowledge of piece value isn’t that great so you tell me.