On the glowing recommendation of a few local ex-pats, I tried out La Bicicleta Verde in Santiago (http://www.labicicletaverde.com/). It definitely lived up to the reputation.

I took the 7PM night tour, which weaves up through wealthy Las Condes into beautiful, residential Vitacura and back into Santiago through the parks along the river. The guide, Peter, a 4-year vet of Santiago from Kansas, supplied knowledgeable and engaging narration throughout. I had been living in Santiago for 2 months at this point and was not expecting to learn anything new, but Peter showed us sites I had never seen and really gave us the insider scoop. Highlights included the still under-construction Parque Bicentennial and various bridges along the Mapucho river. Just the right balance of talking and biking. And it's great biking at night (without the crowds) with someone who knows his way around.

Also, I didn't realize until the tour, but the entire route was essentially downhill. About as strenuous as a walk in the park.

The tour finished at a relaxing bar in bohemian Bellavista, where Peter stuck around with us and shared some pisco sours and tapas. Bicicleta Verde even picked up the bill!

Great time -- recommended to anyone, visitors and locals alike.