Well, they are doing it again! Restaurant.com has an 80% off sale. You can get a $25 certificate for $2!!! Enter discount code: DINE at checkout. This sale ends February 28th.
I have had good success with this company in the past. In fact, we will use a coupon I purchased during their last 80% off sale this week while we are skiing - I don't just use them for restaurants at home, I also pick up certificates for vacations. You do have to carefully read the restrictions and make sure you are comfortable following them, but overall it can be a great deal!