Unlike the alleged shadiness going on at San Francisco Quiznos, IHOP really is giving it up for free today. Fat Tuesday, you see, is also the annual "International House of Pancake Day," where you get a free shortstack (three) of buttermilk pancakes. All that the benevolent folks at IHOP ask for in return is a small donation to a local children's hospital. And it's totally optional!
San Francisco has three two locations (2299 Lombard, 200 Beach, 832 Mission) and Daly City has one (2398 Junipero Serra Blvd). You have until 10 p.m to get your free sugar/carb fix.
Update: According to SFist commenter aj, it's also free taco day at Jack in the Box. Your move, Alice.
