Google has a feature, Mail Goggles, which allows you to set times of the week when you need to test your sobriety/wakefulness before sending an email, by answering some maths problems.
I wish my knitting came with something similar. After knitting the all the waist deceases of Demeter, I decided I wasn't using the right needles, so ripped it all off and started with new needles. What would you know, two attempts later, I went back to the initial needles. The first cast on ended up twisted, the second progress only to discover all my decreases were wrong.
So I'm about to cast on again (it's not too late), starting a new ball of yarn, I think the current one needs a rest.