My mom used to cater and Shawn is right on the money!
Mom would use olive oil and a little seasoning on the pasta too to keep it fresh and tasty! You know, a little basil,thyme,garlic, etc.

She made the best spaghetti and we're German desent!

I have done 2 of our Italian Dinners. We have ours catered by Broadway Pizza, and they serve pizza, spaghetti, salad, and a roll. They provide the condiments as well. We provide a cookie, pop, plates and napkins. It usually costs us about $5 for adults and $3 for kids, in turn we only charge $6 for adults and $4 for kids. It is a family night and not meant to make money. We break even or lose a little bit. We hold the dinner the same night as our book fair. There really isnt time for us to make the food at school before the dinner starts.

The best way, I've seen to do that much spaghetti (I worked for a SPaghetti/Chili restauarant eons ago)
Cook the spahgetti after each pot is done, put it in an ice bath (sink full of ice H2O, stops the cooking) then put in a big tub, toss with olive oil, then all you do is reheat (by pan warmer, microwave, or steamer (cafeteria warmer)

Our school is holding a spaghetti dinner on Nov. 11th. Has anyone done one at their school? I'm looking for ideas on how to cook enough spaghetti for 400 without having mush to serve. Help!