Champagne Vinegar!!! http://planetgreen.discovery.com/food-health/save-leftover-champange.html

If it's not excellent champagne (hello Korbel), I use it as cooking wine. That's how I used up mine this year--lots of risotto making.

You can use it in a gelee, and add some cubed fruit. You could also possibly use it, in a vinaigrette. Or, you can make champagne cupcakes. There is a recipe for it at yumsugar.com, http://www.yumsugar.com/Champagne-Cupcakes-21077844.

brave tart just sent out an e-mail with a recipe for gluten free champagne marshmallows.

Champagne is the preferred wine for making caramelized onions. Slice eight onions thin. Put in greased dutch oven, put a few tablespoons of butter on top, and bake covered for 1 hour @400. Stir. Return to oven with lid ajar, bake 1.5 hours. Take out of oven, put on medium high heat, and cook down until moisture evaporates. When the onions get crusty, put in 1/4 cup champagne to deglaze. Cook down again, repeating the deglazing process until the onions are dark brown. Don't use sweet onions for this or it will taste like something you put on pancakes.
Use in baked goods to give a stubborn cake a lift. I made a ginger cake with champagne and it was amazing. The creamy caramel icing didn't hurt either.
Gelatin and aspics made with champagne are pretty dreamy, almost cake-like. You can make some very gourmet jello shots this way.
It makes a nice braising liquid for white meat chicken and veal. Braise chicken breasts, reduce the liquid, add some lemon, salt, perhaps a few tempered egg yolks, butter, capers, basil. Cod might go for the same treatment, possibly salmon as well.

Make champagne jelly! Jelly isn't difficult to make, and champagne jelly would be an elegant treat, or a special gift for someone, like a bride to be.

Have a post-New-Year's champagne party and mix up yummy drinks! Champagne cocktails! French 75s! Kir Royale!

a champagne beurre blanc sauce for seafood.

Champagne Mussels:
http://www.sheknows.com/food-and-recipes/articles/807160/new-years-recipes-mussels-and-champagne

just came across this recipe today. doesn't use much champagne, but looks delicious.

http://iambaker.net/dark-chocolate-cookies-champagne-buttercream-recipe

Champagne jelly! It's really good for a brunch. You could even make a St Germain & Champagne jelly (with some lemon/orange zest or lychee bits even). That would be great with chevre & crackers.

I second the vinaigrette idea also - on a pear arugula salad with roast chicken.

Champagne grapefruit (or raspberry) sorbet! David Lebovitz has a fantastic recipe. It's not even that cold out these days, so frozen treats seem justified.

Champagne Risotto. http://bit.ly/c0acnY

I poured a little leftover champagne in when I was roasting a chicken with some lemon and herbs. Added some honey as well to help get the skin crispy and brown. Came out tasting wonderful.

mmm...bathe in it!

Truffles, sabayon, try Foodily for more ideas:

http://www.foodily.com/s/champagne

And also on Foodily, I spied a recipe for pear mimosas, I'm heading into the kitchen to make them now... *g*

Sabayon: http://www.epicurious.com/recipes/food/views/Orange-Champagne-Sabayon-364689

champagne frosting and/or champagne cupcakes!

You could probably let it go flat and freeze it in ice cubes. Use as you would any white wine for cooking. Also: salad dressing!

Sweetapolita has a recipe for champagne cake pops, and I've seen a champagne mousse somewhere on the interweb.

Definitely champagne in sorbet. Delicious.

yuuuuummmm champagne risotto! its delicious!

Champagne poached salmon for Saturday night, cold salmon for Sunday brunch!

http://simplyrecipes.com/recipes/poached_salmon/

I forgot, you could also use it to make champagne chocolate truffles

Perhaps you can freeze them into champagne ice cubes? Might end up tasty in a glass of orange juice... :)

Mimosa granita!
http://www.foodcrossing.com/2011/05/mimosa-granita/

I was barbecuing chicken the day after New Year and had a bit of champagne left over, so I chucked it in to the marinade. Turned out great!

Champagne Risotto, it's delicious, one of my husband's favorite dish (http://www.foodnetwork.com/recipes/giada-de-laurentiis/champagne-risotto-recipe/index.html)