You dont have a single friend with a teen aged daughter that would like to play "mothers helper" for a bit?
Maybe just after school to play with the kids at the church thing and ferret the little one out of the tubes? Heck, even one of your friends with a slightly older child (six, eight?) would work for ferreting...set up a play date!
I do not envy you... when we get together with my friend on the weekend we have 7-8 total all under 9 years but there are always 2-3 adults...that would DRIVE ME NUTS!!!!
-Does your local library have story time?
-Can you put in a a kids dance video? (or if you have on demand i think this is listed under "fitness"?)
-Simon says is your friend.
I'm sorry to hear about your niece. I will surely keep her and her family in my prayers. How long do you have her sibs for?