Sometimes when Wyatt is extra bored, I take him for walks to collect stuff to paint. I make a whole thing of it and we bring a bucket to collect everything in. He usually picks up a gazillion rocks and pinecones, but it's fine because it's a total "Wyatt Project" and I let him do whatever he wants.
Painting all his finds usually lasts a good 30 minutes, but that's okay. :)
After painting his latest batch he told me he wanted to put everything in it's own vase in his room.