Gleaming the Cube (also known as A Brother's Justice and Skate or Die; released in the Philippines as Challenge to Win Again) is a 1989 American film directed by Graeme Clifford and starring Christian Slater as Brian Kelly, a 16-year-old skateboarder investigating the death of his adopted Vietnamese brother.

The skating technical advisor for the film was original Z-Boy Stacy Peralta. Among the skateboarders who appear in the film as stunt skaters are Mike McGill, Mark "Gator" Rogowski, Rodney Mullen, Rich Dunlop, Eric Dressen, Lance Mountain, Mike Vallely, Chris Black, Ted Ehr, Natas Kaupas, Chris Borst, and Steve Saiz. Tony Hawk (Buddy) and Tommy Guerrero (Sam), then members of the Bones Brigade, appear in the film as members of Brian's skate crew. Christian Jacobs, future lead singer of The Aquabats and creator of Yo Gabba Gabba!, also appears in the film as Gremic.

The film received a moderate release in the United States from 20th Century Fox (in 469 theaters). Although the film had a relatively low box office turnout, it garnered a significant cult following after its theatrical release, through basic cable replays on networks such as USA and the burgeoning VHS (and later DVD) market, as well as among skateboarders.

The title of the film refers to the cryptic question "Have you ever gleemed [sic] inside a cube?" that Garry Scott Davis (GSD) asked Neil Blender in an interview in the December 1983 issue of Thrasher magazine. In the film, Christian Slater's character defines "gleaming the cube" as "pushing your limits to the edge". The DVD contains an easter egg; by highlighting the skateboard on the main menu, viewers can watch a short featurette entitled "What Does Gleaming the Cube Mean?".