Trying to summon the motivation

I've got 2 younger children who are in sports 5 days a week. When I get a day with nothing on the calendar I tell myself I will get a ton of stuff done, but then that day comes and I struggle to get moving and actually start something. My car is in pieces, and doesn't need much time to be put back together, but the garage is cold, and everything is greasy. Sad excuse to not work on it, but after 5 days a week of leaving the house at 5:30am and not returning till 8pm, sure makes it hard to want to do anything but relax on the random 'day off' that I get