Keep checking for cancellations on the PTN packages. There is a reasonable chance you could still get a reservation. Even if you don't, a nice dinner at BB without having to worry about the tab could be a memorable experience.
A shopping day could be fun, too. Each person would get $100 to spend on something special (e.g. Harvey's bag, D&B bag, Disney art, Wonderground Gallery art, etc.). Discussing and deciding what to buy as you walk through the parks could be a really fun time.
Personally, I would buy a smaller souvenir or have a nice meal, then put the rest down as seed money for my next trip.