A fauxhawk is a fad hairstyle that is either very silly or very sexy. It may be both but it may not be neither.
Properly speaking, the fauxhawk is hair styled so to stick up in the center while apearing normally shorn elsewhere. This is done in suggestion of the haircut named for Mohawk warriors and later stolen by the punk community. It may often be a display of irony as well, in a way that is arguably less offensive than the Mullet.
To make a fauxhawk, one need at least a few inches of hair. Right now, my hair will naturally go into fauxhawk mode after a cycle of showering, sleeping, sweating and changing of t shirt (currently my hair is about two inches long) . Some go to a salon or have a friend style their hair for a fauxhawk. If a Mohawk grows out—ie if the scalp is no longer shaved on the sides, then a fauxhawk is possible.
Some who purposefully style their hair into the fauxhawk will also dye or bleach the tips of their hair. This makes people look stupid and is a waste of money. If you're going to dye your hair, dye it from the roots to the tips. If you don't maintain your hairstyle, your roots will be dyed anyway. Dying the tips of the hair is the equivalent of buying pre-ripped jeans. If the hair is lacking in oil a "product" may be used to make the fauxhawk stick.
As with any trend, it is difficult to pinpoint exactly when the first fauxhawk was made intentionally, tho I would guess that it began around 2005 or 2006. Some people will spell fauxhawk "fohawk". These people have no respect for French cognates.
For a while Brad Pitt had a fauxhawk, as has David Beckham and Ewan McGregor. Note that this is by no means exclusively a guy thing, though a woman with a fauxhawk is liable to draw attention moreso than a man, for whatever reason.
Over time, the fauxhawk has become less and less transgressive but it does continue to mystify some who wonder why kids these days don't comb their hair straight. The fauxhawk will still exist in the future.