CUCaTS
Puzzlehunt 2014
h(x) = 5d6a173a85f618a86ac298e30ece14cd8db92d2f0b626905ec26f3596d4e0dcb
author: unknown
h(x) looks like a cryptographic hash, and refreshing the page shows it changes every 5s. We find that the SHA256 hash of the unix time (floored by 5 seconds) gives us the same hash. Thus the answer is the current unix time (and values within ± a minute are accepted).