Corkscrew
Any bar that serves wine will (hopefully) also need a corkscrew. There are countless variations on this trusty tool, some of them better then others.

My personal favorite is what is often called the "butlers friend". I'll get a good picture of it to post on this page, but short of that, here is a description. It looks similar to a pocket knife, with a short blade that is used to cut the foil around the wine bottle, a corkscrew (or "worm") that folds down from the center, and a "foot" that folds out from the opposite side as the blade. They work well, fit easily into your pocket, and can be relatively inexpensive.

A key thing to look for in any corkscrew, is the type of "worm" that is used to drill into the cork. There are essentially two different types. "Open" worm and "Closed" worm. An Open Worm is far better then a closed one. Lacking proper visuals (at the moment), think of an open worm as looking like the curled tail of a pig, and a closed worm looking like a wood screw with a solid core down the center. The closed worm is basically like pushing a nail down the center of the cork with prongs sticking out the sides that will hopefully provide enough grip to lift the cork back out again. But the softer the cork, the worse the grip.

If you'd like to learn more about corkscrews, you can find out virtually anything you want on the web. In fact, it probably is no suprise to anybody that there is even a website that is totally devoted to the corkscrew. Can you guess it's url? Yep... www.corkscrew.com