I started programming when I was 5 years old in 1979 on a Commodore PET. In those days, the PET came with BASIC and no software, so my father who had brought one home showed me how to write some basic code.
Typical programs I could write at 5 were:
Print "What is your name?"
Input a$
For i = 1 to 100
Print a$ + " is great!"
Next i
We used to go into the local department store and write the following program and leave it running:
Print "K-Mart sucks!"
Goto 10
The average sales person at the time wouldn't know how to stop the program and have to turn off the computer!
This was cool stuff when I was 5. I started working with LOGO as well at an early age as well, doing lots of interesting things with turtle graphics, geometry, etc.
My daughter is now five, so I've been looking for programming languages to introduce her to programming concepts. The problem is that any programming language simple enough for a 5 year old is very lame by a modern computer's standards. LOGO was a big deal in 1979 because drawing a circle, a line, a square, etc. was pretty cool. When I showed my daughter LOGO this year, her reaction was, "That's all it does? I think I'll just go to a web site instead."
MIT has just published a new programming language that is graphical based, uses draggable commands and is focused on sound, animation, pictures, etc. I tested it out this evening with my daughter and it was a big hit! We created some animations together, did some drawing, added some sounds, etc. and then showed it to mom before bed.
If you have children or are simply interested, you can download the software here.