Last summer, for the first time ever, I enrolled my kids in a summer recreation program. They were only there 2 to 3 days per week until 3:00 so I could go to work. They
hated it. So, this year, I decided to quit that job and work contractually from home for multiple clients. I love it!
This summer will be the test though. My kids will be 11 and 9, so they can entertain themselves pretty well as long as they're getting along

They understand that I quit the job so I could be home with them, but that I'll still have some work to do. So far, they are very, very willing to do whatever it takes to keep it that way.
In the summer, they sleep in, so I can work in the mornings. And, with well-planned playdates, I usually buy myself some time. I've also found that if I promise to do "something fun" with them when I'm finished with my work task, they usually don't disturb me. The key is to follow through on my promise.