The best way to serve that large a group is to cook the pasta half way, i.e. very al dente, then combine it with the sauce in a hotel pan or Nesco roaster and finish in the oven. (Covered with foil.)
Just be sure to take it out of the heat before it is tender. It will continue to cook so pull it when it is al dente.
It is easier to do with thicker pastas like mostaccioli that are harder to overcook. Don't do angel hair, go with thick spaghetti or fettucini. The thinner pasta may be perfect when you serve the first diner but it will have turned to mush before the last ones go through, remember, you have to serve it hot!
Thanks for this tip, I think this is what we're going to want to go with, technique wise, but I'm not sure I have the concept down. I think I understand the basic concept, but what I'm not sure is the time frames that I should be expecting here. When I cover with foil and put in the oven what time frame should I be expecting it to finish? Just a ball park estimate would be fine, I can experiment ahead of time to fine tune. Also what oven temperature am I looking at?
What we're currently looking at is a Spaghetti with Marinara, Fettuccine Alfredo, and Pesto, but I'm still not sure what type of pasta we want to do it with. We wanted to get a little more creative, but I'm not thinking the pallets of the people we're serving are going to be terribly adventurous.
Also we want to serve a salad as an appetizer with bread and oil/vinegar, what kind of salad would you all recommend, and tips for mass salad prep?
One more thing

We want to serve home made gelato. We've done about ten different batches in three sessions (for some reason my girlfriend had four ice cream makers sitting around her place). I don't think we'll be serving competition gelato by any stretch, but I think what we're coming out with is going to please most people. The only real problem that we're having is with the sweet cream flavor. It tastes too eggy. We think it might be from sitting in the fridge overnight, but we're not sure. We did one batch with 2 egg yokes with 2oz sugar to 16oz milk, 8 oz half and half, and it turned out great, no overnight set, but it seems like it picked up a more eggy tast the next day. We did another batch that had 1 egg yoke with 2oz sugar to 16oz milk and 8 oz whipping cream, let it sit in the fridge overnight and then put it in the ice cream maker, it seemed to have a stronger egg taste with half the egg in it. We were told that "authentic" gelato has egg yolks in it, which I'm sure it does, but it just doesn't seem like the stuff I was getting in Italy had such a strong egg taste. The original recipe calls for 4 egg yolks, which just seems extreme, help?
The recipe we are basing off of can be found here...
http://allrecipes.com/Recipe/Gelato/Detail.aspxThanks guys,
Dustin