What series has been played on the most number of channels? For example, SNL is syndicated on Comedy Central (80s/90s stuff), E! (70s stuff) and of course the current season is on NBC. Has any other series beaten that?
If you’re talking syndication then I would guess Seinfeld or MASH*. Seinfeld is run in syndication on TBS, and I’ve seen it run on ABC and Fox affiliates in different places. Same goes for MAS*H, but Seinfeld seems more prevalent these days.
Considering that local affiliates of the major networks have their choice of what they want to show in syndication, I’d say it’s impossible to know.
Walt Disney under various names (Disneyland, Walt Disneys Wonderful world of color,Walt Disney, Disneys Magical World,) aired
1954-1961 on ABC
1961-1975 on NBc
1981-1983 on CBS
1986-1988 on ABC
1988-1990 on NBC
now back on ABC
not counting reruns on Disney Channel
It depends on what you mean “most channels”? Independent stations? Networks? Cable? Non-cable? Syndicated reruns or original episodes.
“I Love Lucy” probably is the champ if you mean number of stations. It was on affiliates of all networks, plus independents, in cities around the U.S., and often switched from one to another. It’s also had more time to be broadcast than more modern shows.
If you mean playing original episodes on networks, there are four shows that played on four networks: “The Arthur Murray Party,” “Down You Go,” “The Original Amateur Hour,” and “Pantomime Quiz.” The latter was on most recently, going off the air in 1963. (Yes, there was a fourth network – Dumont – in the early days of TV.)
Law & Order (various flavors) were for a short time on NBC, A&E, TNT and USA at the same time (making the numbers of hours of L&O you could see in a day roughly 25 
). Now it’s on all of them but A&E.
Tom Corbett, Space Cadet was on 4 networks:
http://www.solarguard.com/tchome.htm
Brian