child care and school are two things but the 12 hours alone if you could manage it you could also do part time sample jobs outside the home.
Join up with some of the content writing sights on the web that cost nothing to join and really dig into the forums and information the other writers have shared so you can learn how to do it.
Like reading and writing? It won't pay you anything but it sounds like you are looking for a "title" or purpose....join some book review sights. Perks: Plenty of reading material, published reviews, and being able to tell people you review books (or fancy it up) and most people don't realize how easy it is.
Start a blog. Blog about your kids, your husband, your search for fulfillment..whatever you want. Look at the movie Julie & Julia for how big a blog can grow if you dedicate yourself to it.
Offer to sew or mend other's items.
Become an elderly assistant. Or advertise your willing to go shopping for/with disabled/elderly.
Start a home class for after school. There are a couple of things offered here after school in mom's homes like drama and art classes.