A friend of mine at my clients, Tyler Maxwell, pointed me at a 3D version of Conway's Game of Life he did in Java as an undergrad.  I was suprised by it, as it's an older Java application, yet it's performance using an orthographic view of 3D life is surprisingly snappy.  I guess, given Tyler's skill set, I shouldn't have been surprised.  He's pretty sharp.  The game is available here