Today’s invention is a combination of social networking and exercise technology.
It consists of a regular gps running device with a phone built in. When running in a big event, information about your distance and heartbeat is automatically provided to your Twitter followers (especially tagged eg #exhortation if the readings indicate that you were flagging or in distress).
The followers can then tweet replies which are text-to-speech-ed, via a small loudspeaker, so that you can hear their words of support.