Something to chew on while planning your RPGs... and keep an eye out when playing them!
At their best, mini-games offer players a meaningful way to test their skills in an alternative game setting. At worst, they're either incomplete or make little sense within the game's context. Before peppering your next RPG with mini-games, it is imperative that you consider their purpose, immersion factor and development time. Oh, and don't forget: they should also be fun.