Car2go is offering free membership + free 30 minutes of driving time if you sign up right now. Membership is usually $35 alone and driving time is worth at least another $7-$8.
The official code is: CAR2GOTIME, but the link should take you directly to the micro page for the deal.
Here is a link to the page.
You can use your Car2go membership in any North American city that currently have the service, which currently includes
-Toronto
-Vancouver
-Montreal
-Calgary
-Austin
-San Diego
-Washington D.C.
-Portland, Oregon
-Miami
-Seattle
-South Bay, LA
-Minneapolis
-Columbus
-Denver
-Saint Paul, Minnesota
-Brooklyn
-Eugene, Oregon