I know that you said that you are working on house projects-if you can get around those try a sleepover. My sons are turning 9 and 12 within the next 2 weeks so we are having a combo party for them. We used to go bowling/jump houses/etc, but last year we had a big sleepover-19 kids all together. They played video games, movies, and had nerf wars all night. This Saturday is the 2nd annual event. 25 kids invited this time

We bought eveyone coming a nerf gun as their party treat ($3.00 each on rollback at
Walmart) and they want me to grill burgers, hot dogs, and brats. We ordered 9 large pizzas last year and had 5 full pizzas left.
It will be loud, but fun. Last year not one thing got broken, everyone was respectful and got along. We let them invite more this year and I know it will go just as well. I am going to take PP advise and get stuff for ice cream sundaes. We really love having a party this way. My kids and their friends tell us that they prefer to stay home and hang out and the parents of their friends tell us that the kids love it. I think it is because we don't mind the loud craziness.
PP here: Ditto on the pizza leftover comment...I ordered 4 large pizzas for the 5 boys and worried they would run out. They only ate 1 1/2 and DH and I ended up eating the rest for 3 days after in our lunches and as family dinner the next night. But they TORE UP those ice cream sundaes!!!