YMCA would be really fun. And its really cheap(especially if you know someone who is a member that could book it for you.) They have swimming in the pool(with 2 lifeguards present) for 1 hr. 15 mins. Then you go to a party room for cake/icecream/snacks/game or two/presents. I did one for my 5yr old a few yrs ago and it was only like $85 for two hours for up to 40 kids. Someone would need to get in the pool with them, but its heated and they have the zero-entry pool with splashers, buckets and squirters etc. Just a thought! I set up a table w/snacks mainly for the parents while the kids were swimming, then did cake/icecream and presents. Its simple and quick and cheap! Plus she could invite anyone and everyone she wanted and didn't have to worry about RSVP's! I opted to not do goodie bags since it wasn't in my budget that year. Instead they all got a big guitar shaped necklace that was bubbles since she did a rockstar theme party!