SUMMARY: Found a thing he really loves.
Turned on the hose sprayer to spray something off my shoe, and Chip went wild! He loves madly dashing after the hose spray and doesn't seem to care whether he gets wet.
I've wanted a dog who does that--makes it SO much easier when it's hot to cool them down. Boost likes it, but if she gets sprayed in the face too often, she backs off. Plus she grabs towards the sprayer, and I'm always afraid that she'll hurt her teeth. But the two of them got a few minutes of fun play in the hose this afternoon.
Too bad there's a major drought; can't do this very often.