Always carry or wear some form of identification and emergency contact info; particularly, if you ever ride alone or don't read any further in this section! Somebody or something needs to speak for you if you can't.
We believe this is important enough that Summit Biking provides a Medical ID helmet sticker as part of your Summit Biking membership. Contact Us if you would like one and didn't not receive it when you joined.
Alternatively, you can print up (and laminate) something of your own, use one of the commercially available products such as Road ID or Xtreme Sports ID that provide full featured Internet access to information you enter on their site, or at a minimum, carry your driver's license and medical insurance card.