This suggestion only works in more developed countries and in lodging above the hostel level: use the hairdryer now generally standard in most hotels and B&Bs to assist drying socks. I agree no sock seems to dry overnight in normal climates, but I have found that firing up the hairdryer and inserting the nozzle into the sock's opening for no more than 60 seconds at a time will help dry socks overnight so that they're ready the following morning. The 60 seconds is fairly arbitrary but addresses the concern that the hairdryer isn't getting proper ventilation or might shortcircuit when used in this clearly unconventional manner.

I do occasionally have to touch up the sock with a second hairdrying the following morning, but this technique tends to work with most socks and allows you to skip the purchase of much more expensive socks that claim the ability to air dry overnight.