In 1989 I was taking an Art History course at my local college, and after a couple week's discussion of Mesopotamia, we moved to Egypt. My teacher mentioned 'Ra', but pronounced as 'Ray', when I countered thinking it was 'Rah', she looked at me, and said, take out a sheet of paper and write down all the Egyptian gods you know - you'll get an extra credit point for every correct one.
Most people only put down 1 - 3 gods, yet I was able to list 18 different gods based on memory from Deities and Demigods. After that I became the teacher's pet. She thought I was some kind of amateur mythologian, and I didn't have the heart to tell her, I learned all that from D&D.
However, I was good at history and art history anyway - as a personal hobby. So the knowing of the Egyptian gods just put me in the forefront of the class.
That isn't the only instance of D&D giving me a leg up in the educational system, but that's my most notable one.
GP