Something that always bugged me about knitted ties was the point - or lack thereof. They all seem to be either square or diagonal, but there were no really tie shaped ties. Here is my solution, presented as a House Tie. I realize that a perfectly authentic House tie would have diagonal stripes, but given a choice between diagonal stripes or a pointed point, I went with the point.

For Gryffindor, use 1 ball each of Red Poppy and Saffron.
For Ravenclaw, use 1 ball each of Indigo and Brushed Silver (replace Brushed Silver with Saffron for book version).
For Slytherin, use 1 ball each of Pistachio and Brushed Silver.
For Hufflepuff, use 1 ball each of Saffron and Black Licorice.

Note: Original sample knit with Mission Falls 1824 Wool, which is no longer available