Curiously, some time ago, some friends and I were making a project about a game for Land before Time... it got out, since we got separated... anyways, besides normal tasks, we included shorter quests, the sidequests, in other words.
Sure, it would probably take a storyline for a sidequest, but there is another way of including them: quests inside quests. For example, decisions on what to do with object X, whther to give it to Y or to Z, assuming Z is the original character that asked for the item.
I hope I didn't make it too confusing...?