Valentines Day gift for my conservative, quiet, academic boyfriend?

My boyfriend is a nerdy-acadmeic type. He’s pretty conservative, and I’m pretty liberal… So he usually expects me to bring some fun and excitement to the relationship. But what do I get someone like him for Valentine’s Day? He doesn’t like gimmicks or for me to spend a lot of time and money on him, but I know he will expect a creative gesture of some sort… Normally, I get him books. But I would really like to do something fun and surprising this year. Any ideas?