Sounds good to me, although of course you'd want to either limit the noprocrast lock-out time or allow a "let me in an hour from now" override to prevent permanent lock-outs.

Or, if your concern is simply that YC-funded companies aren't getting work done, you could just lock them out for a couple of hours in the middle of the day. I wouldn't complain about that. :-)

What if instead of an override link it made you answer a Mechanical Turk question? Then at least you'd be accomplishing something useful with your procrastination.

Which problem(s) are you trying to solve? Is it simply the time sink?

If you think folks spend too much time here, then why not a daily limit? Make noprocrast a fixed limit for everyone.

If you think quality would improve during "open" hours, then why not limit submissions to certain hours? Read-access all the time, but write-access only sometimes.

Good idea! Noprocrast with override option is (for me) about as effective as hiding the ice cream beneath a bag of frozen peas would be for a kid.

You could limit the max length of minaway to prevent people from accidentally blocking the site forever. I think max is about 190 years at moment (although if a singularity occured that could become a relevant timespan for procrastinators).