What’s sad is that I actually do this, but while driving for long distances on road trips.
For each mile marker you pass, factor it into primes. Easier on the west end of an even-numbered interstate; more difficult as you travel east. It’s great for keeping your mind awake. Unless you hate math… then it might be great for falling asleep at the wheel.
But in fairness, I’ve never made a mathematical formula for the best way to make a sandwich.
i will hold off comments on your extreme nerdiness and say that i have discovered my new favourite web comic! thanks ;-)