As a Dungeon Master, I'm happy if I can plan one side quest that seems interesting. Besides that, pretty much every side quest has to be off-the-cuff, and my brain is too quantitative for that.
So I'm playing Oblivion (PS3) and appreciating how every town or larger has at least 10 side quests in it. Since I love the idea of players living in a world where there is Too Much going on, I want to be able to recreate Oblivion's depth.
The first solution I think of: whenever a potential side quest pops up, ask the players themselves for the details. One chooses a location, another chooses a person, one person an object, and one an event or organization. This info should be enough to start a completely random side quest, as I use my limited improv skills to fill in the blanks.
Has anyone tried this? Or do you have other side quest ideas?