Yes, it's another fairly phony anniversary but it's an interesting one - supposedly, June 25th is the day that the first real broadcast of colour TV was made in the U.S. (I think it's honestly impossible to track the very first one, but some think there's evidence to select June 25th.)

But almost no one saw it. Not only were there no real colour sets in those days (1951) but because it was the CBS colour wheel system, no sets in existence at the time could even receive it. 

It's one of the reasons the CBS system died, and why NBC was able to perfect its version, which was compatible with black and white sets, and became the standard.

"On today's date in 1951, at 4:35 p.m. Eastern Time, CBS made what is regarded as the first colour television broadcast. It was an hour-long variety show called Premiere, which featured Arthur Godfrey, Ed Sullivan, Garry Moore, Robert Alda, and Faye Emerson. The chairman of the FCC and both the president and board chairman of CBS also appeared on it. The program was transmitted from CBS's New York City studio to the city, as well as to Boston, Washington, D.C., Baltimore, and Philadelphia.

"Only televisions built for color could pick up the transmission, so most people—those with black-and-white sets—who were tuned to CBS just saw a blank screen. Most of those who were able to view the program saw it at a hotel, in department stores, or in an auditorium. Because of this groundbreaking broadcast, today is known as Colour TV Day."

Colour TV Day

If you're old enough, I wonder if you remember your very first colour TV as a kid. Mine was an Admiral around 1969, and being the neurotic that I am, I drove my family crazy adjusting the tint, trying to get the skin tone right. Never did quite get it.

Here's some rare video of a test of the CBS "colour wheel" system.