The neck tie can have a big effect on whatever you're wearing. It can dress up a pair of jeans, add punch to a blazer, and generally up whatever shirt you're wearing...provided it has a collar.
But sometimes, you wanna control the "up." There are lots occassions where your finest silk is a little overkill, or that perfectly balanced double-windsor can actually make you overdressed. In those occassions, when you need just a bit of extra style, give the just-casual-enough knit tie a shot...and while you're at it, make it yourself.
Nicole from the Purl Bee offers these two patterns for a "reverse stockinette" and a "Fair Isle" tie. You can make both with a small skein of each color, and would make for a great way to spend a gray winter weekend while watching a great film. Go do it!