Common dilemma, you have a party, friends bring over wine and then leave you with 1/2 empty bottles of wine at your house. 
How long and what can you do with the wine.

The answer- Whites  will last about three days in the fridge.  

Red - Keep out of the light and it will also last for a few days.

Being the Gourmet Diva, I can't let wine go to waste. A few suggestions on what to do with the wine.

1. Call me over for a drink

2. Freeze the wine in ice cubes. Frozen wine can add great flavor to lemon aid or orange juice. You can even take the wine cubes and make freezes with them. Frozen wine can be a refreshing summer treat.

3.  Use it to cook with, you can make stews or sauces.

I found this great article from WikiHow.

Before Opening

1. Keep it in the dark. Store all wines away from light, especially direct sunlight and fluorescent fixtures. UV rays can cause wine to be 'light struck' picking an unpleasant smell.[1] Darker bottles are better protected and some bottles have UV filters built into the glass, but enough UV rays can still penetrate to ruin the wine. If you can't keep a bottle entirely out of the light, keep it lightly wrapped up in a cloth, or simply put the bottle inside a box out of the way. If it does get exposed to light occasionally, try to make sure it's light from incandescent or sodium vapor lamps.[2]
2. Store corked wine bottles on their sides. If they are stored upright for a long amount of time, the corks will dry out, and air will eventually get to the wine, spoiling it. If you store it label side up, it'll be easier to spot any sediments that may have formed in the wine over time when you do eventually pick it up.
3. Keep the temperature constant. For extended aging of wine (over 1 year), refrigeration is a must in most parts of the world; even a below-ground cellar is not cool enough.
   
   
   • Wine storage temperature should never go over 75 degrees F (24°C), except for brief spans of time. At 75°F, wine begins to oxidize. An ideal temperature for storing a varied wine collection is 54°F (12.2°C).[3] Letting the temperature drop below 54°F won't hurt the wine; it'll only slow down the aging process, as long as the temperature doesn't fluctuate dramatically.[4]
   • Temperature in a wine storage area should be as steady as possible; changes should be gradual. A 68 to 73 degree storage area is far preferable to one that is 45 to 65 degrees F, though the first approaches the dangerous 75 figure. Rises in temperature force wine through the cork; drops cause air to be sucked back in. The greater the changes in temperature a wine suffers, the greater the premature aging of the wine from overbreathing. The temperature should never fluctuate more than 3°F (1.6°C) a day and 5°F (2.7°C) a year, especially with red wines, which will suffer more temperature-related problems than white wines.[5]
4. Don't move the wine. If possible, store the wines in such a way that you don't need to move them in order to reach a bottle to drink. Try not to move a bottle at all once it is stored. Even vibrations from heavy traffic, motors, or generators may negatively affect the wine.
5. Keep the humidity at around 70%. High humidity keeps the cork from drying and minimizes evaporation. Don't allow the humidity to go too high over 70%, however, because it can encourage the growth of mold and cause labels to loosen.[6][7] You can purchase a hygrometer to track the moisture conditions and use humidifying or dehumidifying techniques as needed.
6. Isolate the wine. Remember that wine "breathes", so don't store it with anything that has a strong smell because it will permeate through the cork and taint the wine. Good ventilation may help prevent musty odors from entering the wine.[8]
7. Store for an appropriate amount of time. Not all wines improve over time. Generally, new world, inexpensive wines will not improve. Red wines can be stored and aged for anywhere between 2-10 years to mature this, however, depends on the type of red wine and the balance of its sugar, acid and tannins. Most white wines should be consumed after 2-3 years of storage, however select White Burgundies (Chardonnays) can be aged for over 20 years.[9]
8. Adjust the temperature before serving. Different wines taste best at slightly different temperatures, which may vary from the temperature in which they were stored. Right before drinking the wine, allow the temperature to rise or fall to the appropriate serving temperature:[10]
   
   
• Blush, rose and dry white wines: 46-57F (8-14C)
• Sparkling wines and champagne: 43-47F (6-8C)
• Light red wine: 55F (13C)
• Deep red wines: 59-66F (15-19C)

1. Store opened white wine in the refrigerator. This will only keep the wine for three to five days if you have already opened it; make sure the cork is in the bottle as tightly as possible. If you want to keep it in the refrigerator for a longer period of time after opening, purchase a wine stopper and pump, and hope for the best. The important thing is to minimize the wine's exposure to air. If you have a smaller bottle, you may wish to transfer the leftover wine to it, because there will be less air for it to contend with. A wine cellar or closet would be better for it, though, simply because of the long amount of time many people spend with the refrigerator door wide open, letting in large amounts of light, and, if you leave the door open long enough, heat. If you happen to have a refrigerator that you do not use often, such as a pool house refrigerator, keep it there. You may even consider turning a small fridge into a wine refrigerator.
2. Leave red wine out. For the sake of the wine, and for yourself, only do this with red wine, never white. Place the cork in the bottle, put the bottle in a dark place, and don't worry about it. This will help for a couple of days.
3. Keep dessert wines like Sauternes, most everyday Ports and most Sherries for longer. They will resist degradation for more than 3-5 days, though exactly how long depends on the individual wine.[11]

• Wine cellar. This is an obvious one- if you have a wine cellar, worry no more! Just place the bottle of wine on the rack, close the door, and you are set. Make sure to have some type of system for finding certain bottles of wine in your wine cellar, though, otherwise it can be very easy to spend a good amount of time searching for that one particular bottle.
• Makeshift closet wine cellar. While digging a large hole in the basement would seem the most effective thing to do, that would be a major undertaking, and will cost you quite a bit. Only do that if you are an absolute fanatic about wine, and have dozens of bottles in need of long term storage. A closet wine cellar is ideal for the every day wine lover, and will probably only cost you around two, three hundred dollars. The major problem with this, however, is that if you ever want to convert this back to a regular closet, you very well may have to replace all of the sheetrock in the closet.
  
  
  • Find an empty, out of the way closet on the ground floor of your house.
  • Glue strips of 1" foam board to the walls and ceiling of the closet, using construction cement as a glue.
  • Replace the door with an insulated, preferably steel, door. If you would like, also glue the foam to this, just to make sure it is all even.
  • Attach weather stripping to the edges of the door to make sure that no air gets in or out- heat could ruin the wine.
  • Make sure that the temperature is relatively cool. There are numerous devices you can use to decrease the temperature in the closet- just find one that suits your particular closet.
• Wine cooler/refrigerator. This will keep the temperature constant, as long as you only store wine in there so that you're not always opening and closing the door. Good humidity levels are maintained, as well. Some have different temperature zones for different wines.