I just started DMing, and all I have is a vague idea, and some stats. Thats it. The only idea is that the party will be blackmailed by thier employer, a noble who sends them to kill things for him, "protecting the realm." Whether they actually earn the right to be called protectors, well...
Anyway, all I have is that idea, the idea of making them kill goblins, and a whole BUNCH of stats I outright stole from the goblin-a-day thread. Oh, and I helped them all develop backgrounds that are really easilly abusable adventure hooks. (WHAT? My evil father isn't dead? WHAT? My grandfather's quest item is this little ball of fluff? WHAT? That goblin tribe that kileld my family was taken over by the ranger's evil father?)
Thats it.
I've already run a few sessions, with maybe an hour of prep time each. It works pretty well, because since me and my players are all immature highschoolers, I can just throw something wacky at them (like nameing two of the goblins Jay and Bob, or a psudonatural goblin who sucks in her own skin (think that mirror scene in the matrix, but sort of funky)), and they take care of everything themselves. I only facilitate thier... "fun."