This deal has ended.
Restaurant.com is now taking 80% off dining certificates via code SALE through 12/31. This drops the price of a $25 gift certificate, normally $10, to $2. They have a large selection of participating restaurants nationwide (more than 18,000), and you can search by zip code or neighborhood. Be sure to read the fine print for each restaurant, because they all set their own spend thresholds and exclusions such as alcoholic beverages, weekends, or holidays.