Gauntlets, or whatever you want to call them.
Annoyed with my too long trousers (happens often, I have short legs) I whipped out my trusty sewing-machine and fixed that problem in two minutes. Fold, sew, cut excess fabric, didn't bother with anything fancy (though it doesn't look very bad). I aim for a virtual no-viewing policy in that area, not sure if that'll work out, but we'll see. Don't know why anyone would go stare at my hems anyway.
So, while I had the machine out, I decided to make some arm-warmers / gauntlets / watchacallems to wear with my t-shirts. I simply took a bit of fabric in the desired length, measured the width of my hand (ex thumb), took the width twice and cut it out. Then I hemmed all sides to make it easier to handle, and after that folded it, sewing the long sides together with an opening for my thumb. Looking online I found an easy tutorial explaining almost exactly what I did (differences don't really matter anyway).
For fun, I also made myself a little reflector-wristband with push-buttons. Considering stitching something on it...