You know those rings you put around the stems of wine glasses, to mark whose is whose? Well, a friend suggested that people could use them for those portable plastic water bottles, too. So you can tell which is yours when at work, the gym, etc.
The beaded ones I've been making for wine glasses won't work - too "pretty" for plastic bottles, and the beads would slide down the neck and bop the drinker in the mouth.
So a friend suggested using stretchy cord, like the gold or silver type they use for wrapping packages, and then attach some sort of colored dangle to identify whose bottle it is.
A mini-headband, or a pony-tail tie might work, too, if I could figure out how to get the size right.
Any other ideas?