The dogs got "The Dog Fighter" toy by Nina Ottosen from Mama. This is the coolest toy ever. Meet my most food driven, street smartest dog: BUDDY--this made it much more fun.
This is level one: Easy
This is level two: Medium
Level three to come! There are stoppers that I can insert, and then he has to move them before he can slide the cylinders. Then level four looks like it's more suitable for smaller dogs (very small pegs)