When I have an abundance of milk, tapioca pudding, butterscotch pudding or custard are on my list of things to make. I used half a gallon in a single day that way a while back.
For tapioca, I use the recipe on the back of the box of small pearl tapioca. I actually buy the tapioca in bulk now, but I have the recipe I cut off the box in the jar with the pearls. I believe it uses 3 c of milk.
This is the butterscotch pudding recipe I make, and it's fabulous!
http://eggbeater.typepad.com/shuna/2...scotch_pu.html
Or custard/flan. For custard I usually do 2 eggs per 1/2 c of milk. For flan it's more like 2 eggs per cup. Sweeten to taste, add a dash of vanilla.
Or there's also rice pudding - which I'm horrible at making, but love. And you can use a ton of milk with that.