When does a game stop being fun?

I thought this piece on the BBC technology news site was rather interesting. It's clear that there comes a point when unlocking bonuses in games stops being fun and becomes a chore. With some of the MMORPGS this has led to people being paid to play the game to level up a character... so the game stops being a game and becomes a - probably rather tedious - job. But in this particular case I'm wondering how you'd describe the activity taking place?

In a sense the creation of the machine that presses the buttons is a form of play... but if we take that out of the equation and assume that there are people who may actually be doing this manually (i.e. starting a game, quitting then restarting etc.) then what are they doing? It's not work, but nor is it play... so what is it?