Triple Triad is a fun time killer, the problem is that the tournaments are terribly terribly broken and there's no way to place in the top 3 without win-trading. There's all kinds of ways SE could fix that but they haven't bothered to do so.

I think Blitzball could be fun IF we can recruit pre-existing NPCs for our teams like in FF X and if the majority of the content for it isn't PvP.