There are several to choose from, each with its own benifits. Some sights offer genuine discount tickets, but it if seems too good to be true it probably is, or they are trying to sell you timeshares. I don't know of any place that sells discount Disney dinners, however Arabian Nights and Medieval Times often offer discounts on their web page online. If you are planning on going to a Disney show in May you should make your reservations as soon as possible (1800-wdw-dine) because they are very popular and sell out ahead of time.
At Disney:
*Hoop-De-Do Musical Review At The Wilderness Lodge
*Spirit of Aloha Luau at The Polinesian
At Sea World:
*Makahiki Luau (No park admission required)
In Orlando:
*Arabian Nights
*Medieval Times
Each show has a different theme, so pick the one you think your family would enjoy the most. If you are staying on Disney property and you don't have a car, you would have to call a taxi to get to any of the non Disney shows.
Have fun!