Dinner and a show is a great family event. We have been working with school groups for over 20 years and the most successful family nights we have done have been dinner and a show. As a matter of fact it is so successful we have designed special programing for just those types of events.
The show idea brings in a lot more people than just dinner, probably because it makes it a full evening. You can add a little more to the dinner price and offset the cost of a professional performance. I'm sorry I don't have any particulars on the dinner itself but I can give you pointers on how to do the show end of it if you are interested.
We have a spaghetti dinner every year in February in place of our regular PTO meeting. We get our meat for the sauce donated by a local business and purchase the noodles, sauce, garlic bread, salad, milk, and coffee. Parents volunteer to bring in cookies and bars for dessert. We ask for a donation at the dinner and make anywhere from $50 to $250, we don't do this as a fundraiser, we just want to cover costs. The principal and teachers do the cooking and serving as a thank you to the families for the time they contribute to the school. Good luck
Due to our districts strict food preparation guidelines, we cannot prepare food at our school. This includes school wide pot-lucks. For our family night, we had a restaraunt cater the food and charged accordingly. It was used as an opprotunity to gather families together, not a fundraiser. We also had a small raffle with 10 donated items (family related: family photos, movie tickets, etc...). Every family received a free ticket and the raffle was held at the end of the evening. This was our way of giving back to our school and say "thanks" for all of their hard work on our most important fundraisers.
The only other addition to the evening was we had our library bookfair at the same time and they did really well. Keep it simple because it does take time to feed everyone, and if to many activities are going on, they won't get to enjoy it all.