Wind Checker - Cheap and Easy
A while back I read somewhere that if you want to keep an active eye on that wind while in your stand you should get some thread. All you have to do is go into grandma's sewing kit and unreel out the thinnest thread she has.
I usually take enough for the whole season (about 10 feet or so). Curl it up into a ball and put it in with your hunting gear. Once you're in your stand take a nice 4-5 inch piece and tie it to an overhanging branch. You're all set! Now all you have to do is keep a close eye out on that thread. Note: If you forget your thread at home, you can always check the gear you have for hanging thread. (i.e. hat, gloves, jacket, pants, shirt, etc.) Good Luck!