I'll bite... wut?!
If you're asking a user to calculate a hash in their head based on a secret plus the current time when entering a password, you're greatly overestimating the amount of time and mental capacity regular people have.
If OTOH you're talking about using a hash of a secret plus the unhashed current time, your suggestion is completely useless. The hash would be static and simply be a normal static password, and the addition of the current time would be of no extra significance to security. Not to mention that you'll have a hell of a time with clock synchronisation.
To make dynamic hash calculations based on secrets feasible in practice, you need a dingus which does it for you... oh wait, that's a smart card or an OTP device.