Cell Phone Idea (sorry if dupe)
Sorry if this is a dupe, but I just read this in my local cycling group's email list, and I thought I'd share. In England, EMTs are encouraging people who bring cell phones cycling or rock climbing to program "ICE" -- "In Case of Emergency" into the phone as a number the EMT can call to get someone who knows you. This works especially well if you have special medical needs (not as well as an alert bracelet, but better than nothing.)
My cell phone display is large enough to display "EMERGENCY", so I'm using that instead, so that a random passerby finding me with my head caved in will be more inclined to hit that (after calling the paramedics, hopefully.)