You can work at a summer camp, resort, or vacation spot that hires lots of people in the summer. Ditto on the attitude. The advantage here is that you might have the chance to travel. You won't make any money, but the experience can be invaluable. You can get an entry-level job with a small business and learn the business.
Options are endless.
Just open the business section of the phone book or drive around and see what is out there. Drive through small industrial and office centers and knock on doors. It will be helpful if you have a skill the business can use such as typing, computer skills, etc., but that is not necessarily a requirement. Again, make learning the key. Take what you can get and learn, learn, learn.