There’s nothing math geeks like better than prime numbers (well maybe Pi but not much else). There’s no need to constrain your watch to the standard one through twelve when you can do it a little geekier by just showing the primes. The Prime Time Prime Numbers Watch shows the prime numbers in bold and breaks down all the non-prime numbers into their prime roots. Don’t worry if you don’t know remember too much about prime numbers from your school days-
you’re just really old and slow you can just use the watch hands like a normal watch. $34.99 from ThinkGeek.