CUCaTS
Puzzlehunt 2014
h(x) = 578484d50b7ed0daa8c309b3116333d0eb03e3c0d4d42c0982864f112b9ef5d0
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).