Time Cube was a pseudoscientific personal web page set up in 1997 by Otis Eugene "Gene" Ray. It was a self-published outlet for Ray's "theory of everything", also called "Time Cube", which claims that all modern sciences are participating in a worldwide conspiracy to omit his theory, which posits that each day actually consists of four days occurring simultaneously. Ray described himself as the "wisest man on earth" and a "godlike being with superior intelligence who has absolute evidence and proof" for his views. Ray asserted repeatedly and variously that the academic world had not taken Time Cube seriously.

The Time Cube website registration expired in August 2015.