Feeling the pressure

Courtney's 4th birthday party is a week from this coming Saturday. It looks like there will be 7 kids there, including mine. I cant seem to come up with ideas for activities for them. Here's my thoughts so far:

1) I was thinking about buying some of those plain brown craft box things for each kid and letting them decorate the box with stuff that can be glued on them and maybe send some candy in it and that would be their party favor and a keepsake.
2)I am also thinking about blowing up some balloons and putting them out in the backyard and letting them hit them around to each other, like balloon volleyball or something of that sort. I know that Courtney LOVES to play that so other kids might too.
3) Ive also got some sidewalk chalk and a sandbox. I really dont want to get them in the sandbox because sometimes its a mess to clean them up when they are done and we just got new wood floors and my husband has told me to becareful about letting sand get on it. Also we have a swingset they could play on.
4)After outside play (if the weather permits it) then they can come inside and eat their cake and ice cream and have Courtney open gifts (although im wondering if i should have her open them around the kids, or if i should wait until they leave?)

Hopefully after that it will come to a pleasant end! Now, if it rains, im not sure what im gonna do. I guess ill just move my coffee table and bring out a bunch of toys into the living room and let them play.

I hate planning parties that involve alot of kids. I felt obligated to invite some of these kids, so I couldnt really get around it. Its probably going to be no big deal, i just stress myself out wayyyyyyyyy too much and wayyyyyyy too soon!!