Roll up and fold or twist a paper towell to stuff in the top of the neck. And finish that wine soon!

What you need, if you regulalry don't drink teh full bottle, is a Vaccuvin. It's the exposure to air that affects the wine, and by pumping it out you can get a good week out of an opened bottle! Cheap and easy to use...but buy a few extra stoppers in case you toss one...

http://www.amazon.com/Vacu-Vin-3-Piece-Saver-Stopper/dp/B00004SAF4/ref=sr_1_1?ie=UTF8&qid=1291537434&sr=8-1

Ooooh.... "Whole Foods does it as do some of the wine stores." That clicked the moment I pressed "submit answer". That makes me flinch.

Always keep extra corks in a bag. Or... Ask a neighbor. Ask a bartender. Ask someone in a restaurant. Drink more wine. Save those corks. You can make trivets or realio trulio cork boards out of them. By the way, depending on where you live, there are stores and wine shops that have bins to recycle corks. Whole Foods out here (The S.F. Bay Area. Yeah those Northern California people.) does it as does some of the wine stores.

(inwardly debating whether I should 'fess up to already having drunk the remainder.... hahaha)

Thanks, betteirene and amysarah! I'll keep both of those in mind, as I'm prone to losing corks, or accidentally feeding them to the garbage disposal (as happened tonight, it turns out).

You could decant the wine into another glass bottle, or even jar, with a relatively airtight lid. Just make sure it's not so big that there's a lot of empty space - the thing is to minimize contact with air. (Storing in a cool, dark place helps too.) Just a thought.

Drink up, my friend. If we don't see you here tomorrow, we'll know you swallowed this advice. : <>

A long, long time ago, I remember crumbling a cork and using a wadded-up piece of plastic wrap to stuff in the neck, then covering the opening with more plastic wrap held in place with a rubber band, but for the life of me, I can't remember if it worked or if I ended up using it in spaghetti sauce. Sorry.