I have posted about this before, but there are more restaurants offering coupons now. And you can get a $25 gift certificate for $2 if you use the code ENTREE by November 12. (And they constantly offer 50-70-80% discounts to people on their email list, so you should never pay the "full" $10 price.)
Check out the list of 23 Howard County restaurants -- heavy on the "bar and grill" but including some unusual places like Iron Bridge Wine Company, La Palapa, Hidden Treasure, and the Elkridge Furnace Inn. They're also accepted at Cuba de Ayer in Burtonsville and both new Japanese steakhouses -- Maruha in Columbia and Ginza of Tokyo next to the Applied Physics Lab on Johns Hopkins Road.
(Update: Read the comments below. Several people, including Alex of the Technology & MSG blog and Kate of the CupcakeRN blog, talk about some hiccups with using the certificates. Brandon left a comment on another post about issues at Frisco Grille so call ahead if you have any questions. Agussman left a comment about buying gift certificates instead of specific restaurant coupons.)