Dont know if the technology is there yet, but the other day i got really baked and thought how cool it would be if the lining of home pools were made to project images through the water... sort of like one giant underwater TV that projects the images through the water and creates 3D environments. If it was possible youd be able to project the images of anything! Like...

-Floating through space (floating underwater with stars and galaxies projected around you)

-Having fish swim around you

-Falling through clouds..

Endless possibilities..