What are some fun things to do at a summer camp?

Note it's a FANTAGE summer camp... XD So, I want to host summer camp at my place on fantage, but last time, heres what happened: They got here, we did a meet and greet, we went swimming at sea breeze, ate at Chez Fantage, went to the Fantage school, and then went back to my place to sleep. This time, I want to do something more. Have any suggestions on what I could do? I was thinking a picnic in the secret area of the grotto... or just in the grotto... Help?