I can't give you a specific recommendation on something that's available all over, but our state university holds middle school science camps that my kids have loved - I think you'll find the same at other universities and colleges, especially schools that are strong in math/science.
My ds has also attended CTY's summer science camps and loved them.
Another possibility are local science camps funded by private industry - there are a few of those in our area too - some in cooperation with a local college, others private.
One thing I found when my kids became middle school age is that local and state camp information wasn't advertised the way younger-age camps were - so I had to do some digging and networking to find out what was actually available. Networking here is great - but you might find something really great through local networking too
polarbear
