I run an art camp for about 5 or 6 weeks every summer. I keep classes small and affordable so it does not feel like "work." These are kids that love art and are often self motivated. Those that come but obviously have no interest, are sent home with a refund.
It is during these summer sessions that I tweak my lessons and experiment with new ideas, some of which I get from the Facebook Art Teacher's group. (It's private so you'll have to ask to join.)
One of our most popular weeks is "CrAzY Art" week where we do things not allowed in a traditional setting, like making paintings by walking through paint and onto a canvas, setting fire to sticks and drawing with home-made charcoal, squirt gun paintings, painting with 3 foot paintbrushes... you get the idea.
Someone posted a nifty idea of putting paint in a tight little lidded container with a bit of water and Alka-seltzer to make exploding paint. We're gonna try that!
I saw an neat exhibition where an artist cut open stuffed animals, filled them with Quickcrete and later took off the skins. They looked like creepy Frankenstein-pets. We're gonna try that too.
As for some more traditional projects. I've done sunset silhouettes
but this time we're going to try moon light silhouettes with tree branches, another project from the facebook group. We'll make some Andrew Goldsworthy style nature projects and photograph them. We'll make a sculpture head with cup up top to grow grass for hair, and a bunch of others. Projects that go well will make it into my public school classes, those that do not, will just be fun experiments.
Summers can be a great time to experiment without an administrator forcing benchmarks or observations upon what you do. Every year I end camp (this my 20th year) I am always anxious to try out new projects when I return to school.