Mine is RFK’s shooting. I was 3.
Maybe watching a bowling match on TV in the late 1950s. For a little kid a ball rolling down a lane and knocking down a bunch of pins and trying to figure out how you keep score was interesting.
There was a program with Walter Cronkite called “20th Century” with a V-2 rocket launching, a view of the earth receding from the ascending earth, ending with a picture of the Rock of Gibraltar (sponsor).
Captain Kangaroo in 1956 or 1957.
Mr. Moose and those ping pong balls.
I also have a very early memory of some scene from the Monkees; it has that same disjointed and surreal character of memories I have from before I was three or so. Which doesn’t make sense, as the Monkees went off the air before I was born. Must have been reruns.
Dr. Who (in black and white)
The Daleks
…and that freakily scary theme song:
Ooooooooo-weeeeeeee-oooooooo
Ooooooooo-weeeeeeee-oooooooo
Some Disco-dancing competition show with different-colored lighted squares on the dance floor.
It was probably Dance Fever; I remember the squares being evenly-lit (compared to, say, Saturday Night Fever).
I remember the Challenger blow up, and I would’ve been 5.
I have a very vague memory of watching Big Bird run the NYC marathon, which according to google, aired in 1983. That would’ve made me like 3 (and only that by two months), which seems pretty young. Do they replay Sesame Street episodes, maybe I saw a later repeat?
Romper Room and Ultra Man in the early 1970s.
I also remember watching repeats of this show that I think was called The Everglades. I clearly remember being fascinated with the airboat in the show with this huge fan.
Could be. Sesame Street not only reruns entire episodes, but they will reuse segments from old episodes in new episodes.
When I saw this, I thought you were mistaken and it was ‘Flipper’ instead.
But… I was wrong.
Google is your friend.
Not that it’s really there, don’t know, haven’t checked, but there’s a chance it might be on YouTube. I have been amazed at how many things from the 50’s and earlier are out there. I have built up my Favorites there from such things. Sadly, some of them get taken down almost as soon as they go up, but even then there’s the thrill of seeing them again for a moment.
Here’s a sample of stuff straight out of my memory:
Adventures of Jim Bowie - Birth of the Knife 1 of 3
I was 2 when Sesame Street made its debut in 1969; I don’t remember life before Sesame Street, so I guess it’s my earliest TV memory. In fact, it may have been the only thing I watched as a toddler.
One of my first also. Another one I remember was Gerald McBoing-Boing (a series of shorts, but they must have been broadcast).
Most mornings I got up before my parents, went downstairs, turned on the TV, and watched “Modern Farmer” (who they though was watching it to farm in New York City is beyond me) and then Farmer Gray cartoons. (That link also advertises a Winky Dink and You DVD in case you really want to regress.)
My family left the U.S. to go to Japan when I was 5. I didn’t see English language TV for the next 6 years.
But in my mind I could remember the half-black, half white – half-white, half-black episode of Star Trek (in it’s original run).
when we returned, it became my favorite show (until TNG came along)
We first got a tv circa 1955 (I was 5 years old) and I recall my parents were excited and the first show we saw was I Remember Mama
Late 1948. Watching the tv guy hook up our set in Arlington VA. He asked me what I was gonna watch. I hadn’t a clue, at four years old. He talked about Howdy Doody. It meant nothing.
Within months, we had crowds at our house, watching the inauguration of Truman. First set on the block. It was all downhill since then. 
OMG, I remember “Rodney and Knish”! It was on Paul Shannon’s Adventure Time on WTAE channel 4 in Pittsburgh. I was growing up in Johnstown, PA and we picked up channel 4 very clearly with our rooftop antenna. I was about 3 or 4 and not only remember Knish and the King Features Popeye cartoons (and other cartoons such as Beetle Bailey and Dick Tracy), but also the old Three Stooges shorts aired daily. Even at that age, I preferred Curly over Shemp and loathed Joe Besser.
Definitely Romper Room, ca 1964 or so. Miss Sally and her magic looking glass. Do-bee and Dont-Bee.
Also Ray Rayner (a Chicago thing), and Garfield Goose (ditto). And of course the cartoons on those shows – Clutch Cargo, Space Angel, Funny Company or the live stuff - Diver Dan, etc. And at Christmas Suzy Snowflake, and Hardrock, Coco, and Joe
I also remember J.P. Patches, but from about 1964. Having a birthday party at the Space Needle was still a big thing then; I seem to recall him advertising such a thing.
As to Fun-O-Rama, it was on about 7:30 in the morning as well as at about 4:00 in the afternoon, or before and after school, as it worked out.
Another thing I recall was a local guy on CHAN-TV, named Peter Roulston, who had a TV show called Pete’s Place.
I also recall seeing the Beatles on Ed Sullivan, because Ed Sullivan was a tradition in our house every weekend. I was into Topo Gigio then, but I remember the Beatles show because my dad just sat there looking kind of disgusted, while my mother kept repeating, “Look at their hair! Look at their hair!”
And then, in December '65, during the Huntley Brinkley Report, seeing commercials announcing, “Batman is Coming!”
However, none of these are my earliest TV memory.
My earliest clear memory is of watching Sky King and then later, while some sports shows were on, of seeing Liberty Mutual Insurance (“The Company That Stands By You!”) commercials showing fairly graphic car accidents. They made a really big impression on me.
BTW, for all of you who mentioned Romper Room:
Romper, stomper, bomper, boo
Tell me, tell me, tell me true,
Magic Mirror, tell me today,
Did all my friends have fun at play?
“I see Michele, and Sigmagirl, and silenus, and over there is robby and squeegee…”