I am having fun with Memrise.com - learning to recognise pieces of classical music, and name the composer. Yes, they're short snippets, but I am learning some of them, and when I hear the whole thing on the radio I listen more carefully. The other day, I was driving along and recognised Chopin's Waltz no. 1 in E flat. But will it stick?
I've often used music and songs to help me learn words, now I find I'm putting words to some of the music to help me to remember the title and composer!
Next thing - learning some of the constellations.