http://www.thewire.com/entertainment/2013/11/movies-and-tv-timeline-kennedy-assassination/355397/

In one "Quantum Leap" episode, Dr. Sam Beckett leapt into the body of Lee Harvey Oswald.

I remember the QUANTUM LEAP one. It was either 2 hours or 2 parts, I forget which.
It was made because the Oliver Stone movie JFK which was out at the time had stirred up all the assassination controversy again.

"Quantum Leap" broke its own rules in the 5th. season and started having Sam do real life celebrity Leaps- which Donald Bellisario had initially stated that they would be steering away from- but oh well, it worked out fine and I love the series all the way through. In fact, some of the celebrity Leaps- particularly this one- are some of the most interesting episodes.
I really liked this episode of the show. Donald Bellisario actually met Lee Harvey Oswald while he was serving in the military and one of the scenes in the episode is based on that meeting. It was also unique for Quantum Leap to have Sam Leaping around so much in different time periods in one guy's life- that really hadn't been seen before on the show. And yes, it was a 2 part episode. And it made for a great 5th. season opener.
Quantum Leap offers an interesting twist on things at the end, but overall- I think it was well done. It offered some insight into Oswald's history and the lone gunman theory about JFK's murder. I generally think it was Lee Harvey Oswald acting alone and I don't get into all the conspiracy theories on this.
But it sure makes for interesting television, as long as it's done respectfully of course. (Which I think "Quantum Leap" certainly was- I can't speak for "Mad Men" or "The X-Files".)
Another show that dealt with the asassination of President John F. Kennedy is "Early Edition"- a two part episode in Season 1 called "The Wall" did a good job dealing with this too.

I remember the QUANTUM LEAP one. It was either 2 hours or 2 parts, I forget which.
It was made because the Oliver Stone movie JFK which was out at the time had stirred up all the assassination controversy again.
Yeah I liked it too, it was also around this time I was discovering the show via reruns on the USA network.