S.R.
Are they both girls? Is this a house party?
My dd had her 9th birthday at the house and we had a ton of kids and did lots of "field day" type of activities in the back yard. Lots of relay races, pin the hair on Hannah Montanna, etc. We did a balloon popping .in the house.
We got inexpensive prizes (i.e. a many packages of things like 12 erasers from the dollar store etc.) and wrapped them up individually so everyone got lots of prizes...then had a treasure hunt at the end for all the leftover prizes.