What exactly is this 40 years next year an anniversary of?
It's already more than 40 years since I first saw the "magic cube" - though not yet the name Rubik. I remember it well: a couple of weeks in the summer of '79 to get a taster of Cambridge before going up in earnest for the autumn term. John Conway demonstrated the cube during a (suitably lighthearted) lecture to us.
After that, I was one of many who bought a cube for myself sometime during my first term there (autumn 1979).