In case you missed their Superbowl commercial or DVR'd through it, Denny's will be giving away one free Grand Slam breakfast (2 eggs, 2 sausage, 2 pancakes) per customer on Tuesday, February 3rd, from 6am to 2pm. From what I can gather this offer is without a catch. You may want to call and confirm with your local Denny's that they're running the promotion. Then, get there early because the info that I've found suggests that they will be giving away coupons and when they run out, the deal is over.
Also supposed to be a full page advertisement in Monday's USA Today.