@Ivan Reese for 3d interfaces, something I find fascinating are non-euclidean spaces (I guess they are not 3d anymore lol). I think they have profound scope for representing multi-dimensional computational concepts yet still being tactile and intuitive. There are not nearly as abstract and mathematical as they sound. Take a look at this awesome video. I love - walking up a hill both ways - the bit at 2:40 where walking through a tunnel makes you smaller alice and wonderland style. This is not representing computation this is experiencing computation from a first person perspective operating on your own perception - the room totally convinces me - it's feels so natural despite being non-euclidean Mind blowing:

This is amazing! Thanks for sharing.

So great!!!

Equally mind bending: