7 Days in Hell July 11, 10 p.m., HBO.

At a little over 40 minutes, HBO’s 7 Days in Hell exists in an odd middle ground between a feature film and an extended sketch. Its parody of pompous sports-history documentaries is mostly spot-on, and at least it doesn’t drag things out any longer than an actual HBO or ESPN special about a monumental sporting event would. The jokes are less successful, and the central premise (about a Wimbledon tennis match that stretched on for seven days) doesn’t really have enough material for even the short running time.

The cast is a mix of comedy pros like Andy Samberg, Will Forte and Fred Armisen along with real-life tennis players (Serena Williams, John McEnroe, Chris Evert) and sports commentators (Jim Lampley, Soledad O’Brien). Game of Thrones star Kit Harington shows surprising comedic chops as dim-witted British tennis prodigy Charles Poole, who faces off against American tennis bad boy Aaron Williams (Samberg). The funniest moments are the odd digressions that have nothing to do with tennis, especially a detour to recount the entire career of a superstar courtroom sketch artist. More unexpected absurdity like that could have expanded the movie to feature length and broadened it beyond a mildly amusing pastiche.