our summer club is great but it does cost a lot. They take the kids to the beach, bowling, activity centres, etc etc and they have access to lots of stuff there, go karts, bikes, outdoor space, they have water fights etc - they have a theme each week and feature activities round that - e.g the olympics or pirates or explorers. They provide activities for kids between 5 and 12 and seem to get the balance right. It does cost a small fortune though - best part of £1k for my two for the 5 weeks, but if I wanted to, I could leave them there between 8am and 6pm
The also put on movies and have wii, xbox and pc's for rainy days as well as craft activities etc.