One of the most enjoyable experiences we had that the whole family enjoyed was the Teamlab experience. You have to plan for this in advance and tickets beforehand as its a popular attraction and wont be able to just turn up.
Getting there takes some effort and a bit of a walk from the metro and there will be queues to get in even with prebought tickets so I recommend going as early as possible – otherwise you might be queuing in the sun.
It has various light/projector installations and each one is unique – photos dont do it justice. If you have young kids I would say that this is a must visit. You can book your tickets from [Official] teamLab Borderless TOKYO, Azabudai Hills.
These are some photos from the place – just go there. You have to experience it.
