The Ryder Gambit is an option you can take within the wider Blackmar-Diemer Gambit. Play continues in the Main Line with 3...Nf6 4.f3 exf3 and then you come to a fork in the road.
Your main option in the Blackmar-Diemer is of course 5.Nf3. There is another less obvious move here though. You can recapture with the Queen instead of the Knight. Yes, 5.Qxf3 is a move!
You're developing your Queen early instead of your minor piece. You're also dropping your remaining central pawn. This must be suicidal right? No because after 5...Qxd4 you have 6.Be3 developing with tempo and preparing to castle long. You are down two pawns but you do have a big lead in development.