CUCaTS
Puzzlehunt 2014
h(x) = 2f51362b0c96089a011257be48cc6696e65f13be877386a0a11480d23ec2dd25
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).