It's a silly idea for a hack. If I can do it for 20 minutes, I can (and will, if necessary) do it for 8 hours; it's getting started with that first 20 minutes that holds me up.

The irony is if you do it for 20 minutes you’ll probably get hooked and go for the next 9 hours - and then that impossible thing will be done :)

this is also really good advice for working out.