Definition of do-athlon

Do: [doo] verb
to perform; to accomplish; to complete; to execute

Triathlon: [trahy-ath-luh n] noun
an athletic contest comprising three consecutive events, swimming, biking and distance running

Do-athlon: [doo-ath-luh n] verbish-noun
term used for actually doing a triathlon

Relay

The relay option is great if you're not sure if you can commit to training for all 3 events.  If you'd like to compete in the relay, let me know and I'll help you set up a team.