...and I say that knowing full-well that one has to first define what "fun" means.
Why am I saying this? Because Destructoid linked to an article by Yehuda about the fact that games are not supposed to be "fun". Yehuda is a smart guy, I've read his stuff in all sorts of places, and he has a fairly-obviously working brain. But this is just sloppy.
The basic contention of his argument is that since games are a medium, they carry no internal obligation to be any particular thing. So I disagree with him right off the bat, which leads to the disagreement over whether or not games should be "fun".
Games are not a medium, they are a conversation. Games exist in many forms that defy categorization as a medium: they may or may not have rules, they may or may not have paraphernalia associated with them (dice, cards, chits, balls, goals, whatever), they may or may not be winnable...there is nothing you can say about games that positively identifies them as a medium.
Conversations can happen in many media: email, instant messaging, phones, inter-office memos, walls of graffiti, etc. Games exist in this space, a medium-independent place where information passes back and forth. So what does this mean, philosophically?
Take a football: look at it. Is that a game? No, it's a ball. A game is the using of it, the interaction that takes place around it. When it isn't being played, it stops being a game. So Yehuda's contention pretty much falls apart for me at that point. A painting exists as itself, and it can be judged as itself. A game is rightly judged by the experience of the interaction within it, and games that don't get people to play are, pretty much by definition, lousy games. They do not successfully do what games need to do to be games, and to be judged as games.
It is here that I insert my definition of "fun". By "fun", I mean, "interesting and engaging". I infer that Yehuda has a fuzzy concept of "fun" that he somewhat sloppily relates to "popular", "successful", maybe "happy". If a game does not interest you and engage you into the playing of it, then it's not a game, it's nothing. Most demonstratively of this, Roshambo is nothing if you're not playing it: it ceases to exist. For it to exist, it must be interesting enough to make people play it. (And play it they do.)