Dyson Logos whipped up some nice-looking character sheets and torch/lantern cards for the Dungeon Crawl Classics RPG. Now, I'm not planning to use DCC any time soon, but the torch/lantern cards are kind of a good idea. But marking and erasing on the cards would be a pain.
Edit: Actually, I guess Dyson didn't create those particular character sheets/cards, he just talks about them.
There's actually a better trick I learned from reading about damage tracking in the Ron Edwards game Sorcerer. If you have a horizontal or vertical number scale marked along the edge of a sheet of paper, you can just slip the number with a paper clip. No pencils or erasers necessary!
So I whipped up my own time tracker sheet, with six turn boxes along the left side and nine boxes on the right. Why nine? If something lasts anywhere from ten to 99 turns (or other time units,) you can use a trick with two paper clips on the right to track the full duration. Full instructions are on the sheet itself.
Licensed under a Creative Commons Attribution-Non-Commercial license.