Here's a great activity to give your dog a great mental workout!
Develop a new behaviour or trick with your dog without showing the dog what you want using a food lure, instead you help the dog work out what it is you have in mind by marking / clicking and rewarding him when he makes very small steps towards the behaviour.
A bit like you're getting warmer..., colder..., warmer...,warmer still...even warmer...red hot!!!...remember playing that game as a child?
Shaping is one of my favourite types of training and free shaping where you just let the dog experiment and offer you different novel behaviours with a new object is the easiest way to have 5 minutes of fun with your high energy dog that will really tire him out!
Here is Ash freeshaping with an old crock pot I found in the garage. I don't have a particular goal behaviour in mind, I just leave it up to him to be creative! :-)