“The Backyardigans: Tale of the Mighty Knights” (7 p.m., Nick Jr.): The Backyardigans go

“The Backyardigans: Tale of the Mighty Knights” (7 p.m., Nick Jr.): The Backyardigans go after a rolling egg. They always get the tough assignments.

“Prison Break” (8 p.m., Fox): Can “Prison Break” get any more preposterous? We’ll find out as the adrenaline-fueled drama returns with fresh episodes tonight. After raising the suspicions of the Panamanian Army, Michael sweats out solitary confinement. Also, Bellick weathers the fight of his life.

“Oswald’s Ghost” (9 p.m., PBS): Maybe it won’t tell you much you don’t already know, but “Oswald’s Ghost” is a haunting documentary that not only deconstructs the events surrounding President Kennedy’s assassination but also helps explain the spell it has cast on America for four decades and counting. Directed by Oliver Stone (“JFK,” “Platoon”), the film includes interviews with author Edward J. Epstein, politician Gary Hart, news anchor Dan Rather, activist Tom Hayden and attorney Mark Lane, among others. Even now, 70 percent of Americans believe that the 46-year-old president’s murder was the result of a conspiracy. “How could someone as inconsequential as Lee Harvey Oswald have killed someone as consequential as John F. Kennedy?” asks historian Robert Dallek, framing the unanswerable question that helps account for the public’s obsession. “Oswald’s Ghost” isn’t so much a film about what happened in Dallas in November 1963, as much as what has happened to America since.