Our neighborhood backs up to the Great Dismal Swamp (great name, huh!) so the mosquitos are completely out of control.
The only repellent we found that works was one I could only find in the hunting department at Wal-Mart. Can't remember the name, but the can is camouflage and it advertises an almost unreal percentage of DEET--somthing like 40% DEET? If you're one of those folks that worries about chemicals, it's not for you with that high concentration, but it's the only thing that lets us go outside in the summer!! We put it on us, and then on the kids where they can't put it in their mouths (spray it on their backs, shoes, socks, shorts, etc.) I also spray the area where we're playing....sandbox, swingset, or whatever....not sure if it helps, but hoping it does.
We did try some of those outdoor area sprays but didn't really notice a difference.
Good luck staying unbitten!
Katie