Noncombat Encounters

In my efforts to try and make sure that the games I run have very little in the way of Empty Scenes, my musing has brought me to the topic of noncombat encounters.  These are, to put thing simply, encounters with NPCs or situations that take place outside the framework of standard combat.  The D&D 4e Skill Challenges are an example of these, and presents a mechanical framework upon which to hang them.