Is there an internal memory on the Nikon D80?

I forgot to put in my memory card and I was wondering if there was any way i could retrieve it, if there's even an internal memory in this camera.

No, unless it said that it would, check out the specs. When you brought it, or the product now… Cameras do usually have an internal memory but that's seen more in compact "point and shoot" type cameras, a Nikon D-80 is officially a low-entry DSLR.

Like most dSLRs, nope, it doesn't have any internal memory.

Most dSLRs do not have internal memory. You could click and the memory card activity light may flicker with no visible warning signs on the LCD. The pictures vanish in thin air though right after that.