I’ve seen a couple of math clocks and watches before, but this geeky pocket watch must be the all-time champ; a product that caters to a subset of a subset of people.
You can order the geek pocket watch at Uncommon Goods for $85 – ($0 x $1) + $32 -$32 (USD). I only recognize four of the twelve equations/symbols/numbers on this watch, but as I said before, you don’t really need to solve any of them because it’s a freakin’ analog clock.