The sidecar is my wife's favorite first drink when we go out for the evening. It has a lovely warming, and at the same time light enlivening, quality that makes it a great pre-dinner cocktail. In fact, some say it was designed as such during WWI for a customer who arrived at the Paris Ritz each night on a motorcycle with a sidecar. Like many cocktails, you can make a "Sidecar" with high or low quality ingrdients. If you want to go cheap, you can shake the following with ice and strain into a cocktail glass.
For a high quality sidecar, do the same only with these instead.
In both cases, you can sugar the rim of the glass and garnish with a lemon sliver, or not, according to taste.
If you feel adventurous some evening, try making one of each of these and you'll see why my wife orders this as her first drink. The former tastes barely passable, the later tastes heavenly, and there's really no middle ground. So, from this one drink she can tell if she has to stick to straight alcohol that she specifies by brand name, or if she can order mixed drinks with impunity and not get burned. She's a tricky one, that wife of mine.
Sources:
http://www.drinkboy.com/Cocktails/recipes/Sidecar.html
http://www.webtender.com/db/drink/820