Do it up like Fred and Ginger (for those unfamiliar with that segment of popular culture: Fred Astaire and Ginger Rogers), in a whirlwind air of Art Deco. Wear a twist of silk, cultivated with a feather and a mysterious drape of a veil, and you have a headpiece.
The fascinator, or it's younger sister, the Bonbon, holds it's own amongst the broadbrimmed hats of the serious hat aficionadas. Presuming that's all on a female head, of course. The French Bibi, and the Calot, widely known in the 1930's, but left un-named pretty much nowadays by the younger set, fit into the fascinator category as well. Smallish, appropriate at a cocktail party, or the Veuve Clicquot Polo Classic, the Bibi can be charming, fetching, and even regal, should it be covered in rhinestones. The Calot, or half-hat, serves a dual purpose: covering the crown of the head for religious and/or Royal Enclosure rules of respect purposes, it can be treated as a headband, and worn much the same way. Often seen on the heads of glamourous movie stars in the 1950's (Grace Kelly, Elizabeth Taylor, Marilyn Monroe) at their watering holes of yore, the Calot was a horse of many colors. Draped in fabric to match an ensemble, or a contrasting textile, it could be beaded, feathered, veiled. It could go to a wedding, or on a yacht. Usually flat, and a tad subtle, the Calot was very well behaved.
Get to know some of these little hats, and let them introduce you to their big sisters.