Ddog is 5 months old and on enforced house/garden arrest for a few weeks after injuring his paw. Can you suggest activities he can do in the house or garden that might wear him out mentally? He's so bored and brimming with puppy energy 
He's not allowed to get wet, which added an additional layer of challenge in the rain last week and we all went a bit stir crazy.
I am using kongs, though that only extends eating time from 90 seconds (bowl) to 5 minutes (frozen kong)... He's a labrador so eating is always done at top speed!
Any ideas to keep him entertained would be very welcome.