Type up a bunch of number and letter codes on the computer, print them out (two copies), and cut out all the codes as seperate strips (for a Twilight twist, the raffle numbers could be things like Forever17, Bella18, or Carlisle362). Put one copy of all the raffle tickets in one container, and the second copy in another. Then when your guests come, have each of them pick a raffle ticket out of one container.
Prizes for the raffle shouldn't be hard to find, unless you're working with a small budget. If you are, then you can still buy some small Twilight merchandise for a reasonable price at Borders or Barnes & Noble. Or you can get some bigger things at Walmart that would only be a couple dollars more (they'll start selling some really cool stuff the week before March 20th).
Or you can make your own prizes for half the cost! Here's how to make some fun Twilight chocolate bars:
1. Buy some candy bars, like Hersheys or Kit Kats.
2. On the computer, you'll have to make some fun chocolate bar wrapper designs. Here's a few designs for Hershey bars here, here, here, and here. And here's some designs for Kit Kat bars here, here, here, and here.
If you choose a different type of candy bar, then, when making your design, the only way to tell what size the image should be is by trial and error. But don't worry, it's not too hard.
3. Print out your designs, and from there it's like wrapping a present--just make sure you leave some extra paper on the top and bottom of the picture so you have enough to wrap around the entire candy bar.
4. To put the picture on the candy bar, make sure you have the image on the front, then take the extra space you left and tape the ends together in back. And vuala! A Twilight chocolate bar!
If you're not sure how to do a raffle, then here's a quick overview: You've already given each guest one copy of a raffle ticket (if you have a small amount of guests, try to get enough prizes for everyone so no one feels left out). Now choose one of the prizes to giveaway, show them what they could get, then, from the second container with all of the second copies of the raffle tickets, pick one out randomly. Read the raffle ticket aloud, and whoever has the other copy of the raffle ticket gets the prize!