It works as a sub in any recipe with white wine---here is one of my favorite chicken recipes using it.

http://www.chow.com/recipes/10530-roasted-rosemary-and-lemon-chicken?tag=search_results;results_list

Vermouth doesn't last forever, but it lasts longer than a regular white wine, so it's great to have it in the fridge for cooking. It's subs very well for anything you might cook with white wine, such as risotto.

Great with mushrooms, as a deglaze.

Use it in place of chinese rice wine in a marinade for stir fries. (wine,soy, garlic, ginger)

I use it as a base for steaming mussels. Throw in some garlic, olive oil, and onions.

a splash of vermouth and some orange or grapefruit juice (no pulp) and ice is a great summer cocktail.
also, I put a tablespoon of dry vermouth on just boiled new potatoes when drained and still hot, adds an interesting flavor, especially if using them for a warm potato salad.

http://www.seriouseats.com/recipes/2010/04/dinner-tonight-parisian-chicken-recipe.html

uses 1/2 a cup of Vermouth at a time..

Vermouth is fabulous in french onion soup, and as sally599 said, can be used as white wine in cooking.

I always use Vermouth instead of white wine for deglazing. It works like a charm!

Use it anytime a recipe calls for a dry white wine.

Replace the brine from a jar of olives with the vermouth, and toss in a sprig of herbs (thyme, rosemary) for easy & delicious cocktail olives.

Oh, woops. I've had an open bottle in the cupboard for months trying to figure out what to do with it. Guess I assumed it kept for ages like other hard liquors.

Almost every tapas joint I went into in Spain threw some into their sangria - that's what I do now, and it's awesome.

I find it doesn't oxidize that fast at all. As long as you put it in the fridge soon after you open it. I keep it for months and months, and use in lieu of white wine.

One of my standard things is making a little bath of water, vermouth, lemon juice, olive oil and thyme and poaching veggies in it, then boiling down the liquid at the end to make a sauce.

Classic martiniss (with gin)

Ha! Ok, so I should toss that bottle of vermouth. Gotcha. (I don't remember when I bought it)

I like it better than most white wines as a cooking wine. I didn't know it should be in the fridge though.

I just saw this one the other day that had me wanting to buy some vermouth: http://simplyrecipes.com/recipes/fingerling_potatoes_with_herb_vinaigrette/

for veal scaloppine (scaloppini) instead of wine: delicious!

My mom fry fresh green beans in cooked bacon fat and tops it off with vermouth. Sounds crazy but delicious.

Add tonic or club soda and lime or lemon over ice for an easy, light summer aperitif. I like white or rose wine this way too.

We keep ours in the drinks cupboard and it's been open a while and still seems to be fine. Pretty much all we use it for is cooking though - any recipe that calls for white wine since we don't always have a bottle open, like we do with red.

I keep a bottle of Vermouth around all the time as I use it regularly for cooking in place of white wine. I've never refrigerated it as I was told because it was fortified it lasted indefinitely.