Now through 10/31/12 at participating Wendy's locations, donate $1 to the Dave Thomas Foundation for Adoption and receive a coupon book containing 10 coupons good for 1 Jr. Frosty (6 oz.) each. At my location, you can also redeem two of these coupons for a small or three for a medium Frosty, not sure how widely accepted that practice is.
Only available in person. Coupons are good until Feb. 1, 2013. When I went in, there was no limit on how many donations you could make.