Yes you'd be surprised by the number of others that jump straight on their bikes without stretching beforehand!
I'd recommend that at least, stretching your legs muscles, (quads, hamstrings, calves, and ankles) and your lower back too is recommended. Remember to warm up before you start stretching though, that's very important! As you say Lisa, if you've been rushing about getting ready beforehand you may be adequately warmed-up... and a brisk walk about for a few minutes will do the trick before you stretch.
You can also do some full body stretches, another nice quick way of stretching out, (such as the Downward Dog you mentioned in another post). Just tried to find some examples of these on BellaOnline but no articles yet so I think I shall write my next article on full body stretches and some quick pre-biking stretches for you too.
Do you do any stretches after your bike ride? One thing I love to do when I'm back home is to use my balance ball to stretch out on! Yay for balance balls!!