Other Car Rental Programs/Partners (ie. Alamo, Enterprise, Sixt) - Enterprise discount code for downtown Chicago?

Does anyone know of a 25% off discount code for Enterprise in Downtown Chicago?

Most of the discount codes show the locations as "not participating". I am renting 10-12 days/month so every bit helps.

No, but the entertainment book specials seem to work.

ETBX7D Free Upgrade entertainment book - to print http://www.enterprise.com/car_rental/deeplinkmap.do?bid=002&cust=ETBX7D&referedPage=multiDivOffer

ETBX7C Free Weekend Day - to print http://www.enterprise.com/car_rental/deeplinkmap.do?bid=002&cust=ETBX7C&referedPage=multiDivOffer

ETBX7B Upto 20% off weekly - to print http://www.enterprise.com/car_rental/deeplinkmap.do?bid=002&cust=ETBX7B&referedPage=multiDivOffer

ETBX7A Upto 20% off daily - to print http://www.enterprise.com/car_rental/deeplinkmap.do?bid=002&cust=ETBX7A&referedPage=multiDivOffer