Um....uh oh.
I don't have a backup bike. Or, rather, I'm riding it right now. It's a K2 T-Nine Crosswind, a cheap hybrid from REI.
Once I get my Surly Long Haul Trucker (w00t!), it will become my primary bike and I can finally take the other one in for a tune-up.
I guess that in a pinch, my backup vehicle would be my gas-guzzling Ford F150 if it starts...or my own two feet if it doesn't.