We've got a tent. It's actually set up on our deck right now and they've been playing in it for the past few weeks. So, even though it's a great idea, I don't think it's "special" enough for an entire Saturday.
Now that DD7 has been in school for almost two weeks, she thinks the weekends have to be something really special. If it's hot, she wants to go to the pool. And I'm okay with that, as long as she and her sister will play in the water and let me read a book!
Otherwise, we may go to the zoo or the park.
The grocery store I go to is also having a sale on Saturday, so we'll have to run up there too. I just wish DH was going to be home at least a little bit because I hate taking them both to the store. Oh well, he leaves early Sat. am and gets home Sunday evening. At least that's one less kid I have to worry about, right?