Putting the "Fun" in "Functional"

Today we all brought along something that was highly functional and something that was fun to use to our studio. We compared these items them categorised them alongside everyone else's.
The functional item I brought were my pliers as they are a tool designed to aid manual construction. The handles have grip on them and are shaped to fit your hand. They make manipulating wire easier and have a bladed edge to cut wire also. They were classified as 'Ergonomic'.
The object I chose that was fun to interact with was my whalebone taonga. The reason I chose it was because despite the fact that it wasn't designed to be played with I would often find myself absent-mindedly fiddling with it. This is likely caused by its smooth flowing shape and texture. It was placed under the 'Aesthetic/Visual' category as is didn't have an actual function apart from being ornamental.

An interesting category that featured was 'Self Evident'. The best example of this was a pair of sunglasses. Their function is self evident as there are a pair of lenses plus arms that are shaped to hang off your ears. Something that has a self evident function is considered well designed as it leads the user to interact with it properly. For our project, however, we can use this idea to mislead the user; to lead them on a track where they think they know the end then to throw them an unexpected experience.
Basic concepts I've come up with so far are several kinetic 'toys'. The first idea was to research into what simple kinetic motions are the most entertaining to perform repeatedly, e.g. pressing a button, flicking a switch or stroking something soft. With the results I would construct an object that incorporates the best of these interactions into its form to make a kinetic toy that satisfies any need to fidget. I am sceptical at the potential of this concept's development, however.
The other 'toy' was designed to play with the user's expectations a bit more. It would be a box of some sort that has levers and switches on it but the motion of these triggers would be transformed within the box so that the output motion would not match the input. The machinery inside this toy could be potentially too complex.