If you don't live in a high-rise building, and you're not Tom Cruise jonesing for stunt work at 53, you don't need to spend the money on a rescue parachute or rappelling system to be prepared in the event of a fire or other emergency requiring a window exit. First Alert's Escape Ladder should do you just fine.
The fire ladder pictured here is First Alert's 2-story version, extending from the window 14' to towards the ground. (They also have a 24', 3-story option in the same Amazon listing). It is strong and stable enough to support children and adults, up to 375 pounds at a time. When not in use the flexible nylon strap sides facilitate folding and stacking its steel rungs for storage in a bin near the window. Completing the ladder's design are an anti-slip epoxy coating on the rungs and secure hooks for quick attachment to windowsills measuring at least 20" high and 32" wide, and between 6" and 13" deep. It arrives fully assembled and setup should take no more than 60 seconds. The system has been tested to American Society for Testing and Materials (ASTM) standards.