Niall read in one of his books about a way to construct a list of all the prime numbers between 0 and 500-something that someone came up with in the 1500's (I think). So he's spent several days now working on doing it himself.
It involves counting by primes and crossing out the multiples, and maybe some other things (I didn't really get an explanation).
He's going to share it with his class and explain the method to them. He thinks it's pretty darn cool. :P