(This reference is going to go over most of your heads by about 20 years. Trust me, it was a great show.)
Two quick safety tips/ideas.
Safety Tip #1. Most cell phone users have probably heard of "ICE" - it means "In Case of Emergency" - it's recommended that you put "ICE" before or after the name of your emergency contact person (mom, dad, wife, husband, etc) in your cell phone contact list. That way, if you're ever in an emergency situation and unable to communicate (ie. unconscious), EMS personnel can easily contact your emergency contact person with your phone.
Safety Tip #2. This one's even better than a cell phone, at least for cycling. This one comes from Angela Quick, who just happens to have one of these on her helmet. Essentially, it's a small card with emergency contact and medical info - I've seen stickers that go inside the helmet, but those fade with time and sweat. This one is compact, easy to see, and firmly secured to the outside of the helmet. See below for pics. The website is helmetgear.ca. I don't have any connection or preference for this particular manufacturer, other than they seem to be Canadian, and Ang has one on her helmet. I'm sure there are other options if you shop around, but regardless of which product you choose, it's a good investment at less than $10.