In games like Skyrim, I already do learn. For example, I can now identify several different types of plant (potato, leek, cabbage) by their above-ground shape and color. It's not tremendously useful, but I can imagine that this sort of compressed pattern-matching experience could teach any sort of rote memorization: periodic table, birdcalls, gross anatomy, musical chords, geography, astronomy, run-time performance of algorithms, etc.... The hard part is getting people to actually want to play your game, so that you can "trick" them into learning.