The other day I was sitting working at the computer feeling quite miserable, because my hands were so cold. Wearing gloves was no good, because I have a lovely Apple magic mouse which is brilliant, but which requires the warmth of bare skin to make the scrolling and navigation functions work.
The solution? Make some gloves that can roll or fold down at the top.
Here are some instructions I put together in a spare moment; hope you can make sense of them.
I've made at least 6 or 7 pairs by now, each better than the rest. I encourage you to experiment until you find a thumb shape that works well for you. Maybe when cutting the slit for your thumb you might like to cut out a few millimetres at the sides, making it a very skinny elongated oval rather than just a slit.
Take note of the warning to ONLY use a ball point needle when sewing stretch fabrics like socks. The seam will run and look very ugly in a short time if you don't. If you really don't have access to a ball point needle and just have to make some of these wonderful gloves (glovvoks? sokkovs?) right now, then use a loose back stitch and sew the thumb in by hand.
Op shops are great places to find cheap socks to experiment on; our local thrift store sells socks for 20 cents a pair.
Good luck, and let me know in the comments how you go!