For those not bold enough to strap on a wingsuit, a Rescue Reel may offer a viable alternative.
The device is small enough to fit in a cabinet file drawer in an office. The user hooks a Kevlar cord to a secure point in the building, steps into the harness, and then can rappel down the wall "without special training."
Stone's major innovation is a centrifugal braking system that automatically controls the rate of descent. The Rescue Reel's cord unwinds from a spool and wraps around a shaft connected to a brake. As the shaft spins, a set of brake pads exerts force on the inner edge of the brake housing, smoothly slowing the user down. Should the automatic brake fail, the device is also equipped with a manual backup brake lever. Descending from 100 stories up takes less than four minutes—about two seconds per story.Personally I have some doubts about how readily one could rappel down a skyscraper without prior training, but if the alternative is incineration...
Reportedly the device is past the concept stage and it will be available next year for about $1500. More details at PopSci, where this received an Invention Award.