I'm nature director of a summer camp here in South Dakota, looking to do some gardening with my campers. The only issue is the camp session lengths are fairly short. I'm hoping to have some fruits or veggies we can eat by the end of the summer and have from June to the middle August to do so.

Any ideas on fast maturing crops we can try and take on?

Lettuce comes to mind, radishes also. Maybe greens, turnips, mustards.
How about tomatoes already in a big gallon pot?DD

Pole beans might work.

Actually, lost of veggies have fast varieties. You can also just look through a garden catalog and watch for the "days to maturity".

Also, if you buy starts from a greenhouse, it will all go much faster too.