What? Straight Bourbon has to be a minimum of 2 years old, aged in new oak barrels, made up of 51% Corn, natural colour, filled into cask at a certain strength, bottled at no higher than a certain strength. Basically, it is a strict set of rules which ensure a very high quality product. Bourbon is credited as "the American Spirit" and is actually enshrined in law as such, so they do take it seriously in the United States. It is a category that survived prohibition in the 1920's/30's and is now booming.
Where? Straight Bourbon can be made anywhere in the United States (but only in the United States). Most Straight Bourbon is made in Kentucky.
When? American Whiskey is as old as the United States itself, but the first mention of Bourbon was in the mid 1800's, with many different people having a claim to creating the category that is Bourbon, including Reverend Elijah Craig (who has quite a story of his own). Now, while we enjoy good stories, we reckon Bourbon as a category has developed over time, not due to one invention.
How? Bourbon can be drank neat, with a mixer, in a cocktail and more. If you were going to the Kentucky Derby (a horse race nicknamed "the greatest 2 minutes in sport"), you would drink a Mint Julep (mint leaf, bourbon, sugar and water) in a silver cup.