So, with this being the week between Christmas and New Years, where most people are busy - or at least heavily distracted - I figure I'll try and keep the posts lighter, less concept heavy, and more prone to the type of things you may be able to do over this week. Such as one shot ideas like this one. Which, like most one shot ideas, is usually a blatant rip off of something the GM has read, played through themselves, or seen recently. In this case, we'll go with the Hunger Games and Battle Royale. How do we do it? Well, read on.
First, for the uninitiated, Battle Royale and the Hunger Games have similar stories. Basically, a group of kids is drawn together, put into an area, given weapons, and very simple instructions. "You fight until only one of you is alive". I won't tell you the particulars of the stories, suffice to say that they are good reads and you should give them a shot if you have the chance. I, personally, just finished The Hunger Games and if nothing else found it to be a read that pulls you in. The use of first person, present tense, for writing is interesting in and of itself.
So, how do we do this for a one shot? Well. First, we have the strengths. There is a story already there, a situation that the players are wrapped up in, but can take and direct for themselves. Do they try to escape? Do they go along with it? Do they fight to survive? To win? How they handle the situation can be a story enough for it, and all you have to do is give them the situation for it.
However, there are problems as well. For one, the "only one victor" thing can be an issue. Though, this is fixed easily enough. Assign people to teams, the PCs just happen to be one of those teams, and need to try to survive and fight through the event. The other issue could be the situation being too dark for a group around now, but well, that is up to you to decide.
Personally, for a quick one shot I do like this situation. Characters are supposed to be low powered, which means less points/feats/whatever, and thus quicker character generation. Also, since with both we're making teenagers/school kids, it opens up the possibilities for stories. People can take a variety of skills - albeit at low ranks usually - and really open up their options. Finally, the situation itself is one with a lot of ways to attack it, and that means if you ran it 2-3 times for the exact same group of players, it could play out 2-3 completely different ways, and that to me is just awesome.
So, if you're stuck for an idea when your family/friends tell you your GMing on short notice. Why not just dump them all into an arena and have them fight it out?