The Springwise Blog has a story on a pilot program in Minneapolis (where I'll be next week) called Get Home Free.  Here's how it works:

Launched in eleven Minneapolis suburbs this month, Get Home Freeis a flat rate, prepaid cab card that gets its holder home safely.Mainly targeted at teenagers and college students, the concept'sinitiators are aiming to help out kids who are stuck with car trouble,have been drinking, or whose ride home has fallen through. Cardholdersplace a call to the Get Home Free hot line, and a car is immediatelydispatched to bring them home, no questions asked.

If your firm is looking for a image-boosting promotion, this one just might work -- especially if you regularly represent clients accused of DUI.  Having your firms name and number on the back of each card isn't a bad idea either.