If the ever-burgeoning number of beer styles overwhelms you to the point that you'd rather knock back a shot of vodka than deal with all of the confusing terminology, consider this single fact: nearly every beer in the world can be categorized as either an ale or a lager (let's discuss lambics another day, shall we?).
See, unlike the humans who judge them, all beers are not created equal. Ales are fermented at a higher temperature for a short amount of time with top-fermenting yeast. Lagers, however, are fermented cold for a longer cycle with bottom-fermenting yeasts. If your head is still spinning and you haven’t even begun drinking, all you need to remember is that ales are generally darker and more robust, while lagers are generally lighter and crisper.
Pilsners are perhaps the lightest and crispest of pale lagers, originating in Plzeň, Bohemia (today, Czech Republic) in 1842. City officials began brewing lager-style beer to improve the typical swill's clarity and shelf life. The result was a golden brew that was an instant smash hit (and also got lots of people smashed).