I think I had the space games one. I remember keying in the moonlander game. What I found interesting was the feelings it stirred in me. I 'remembered' in an emotional way what it was like to be 10 years old and keying in BASIC programs from books and magazines.
One of the other things I remember doing was drawing a pattern of lines radiating out from the centre of the screen. The spacing between the lines would interfere with the video rendering and you'd get lovely moire patterns. Varying the space between the lines would change the pattern.
(Largely because I'd checked them out of the local library so frequently.)