In the past year, the Arborwiki birthday deals page has been updated more than 100 times with news of new birthday specials, changes to existing specials, and restaurants that have closed. It's carefully organized into breakfast, lunch, dinner, and dessert specials, plus a whole set of goods and services that are available at a discount or free on your birthday.
The page is easily the most popular on all of Arborwiki, and it's the one that's most frequently edited.
My personal favorites are the long-standing Northside Grill special (free breakfast or lunch entree; you pay for beverage and tip) and the new Roos Roast special (free any drink at the cafe). Zingerman's used to give out a half dozen bagels at the deli; now they have a range of freebies and discounts that all require at least a token purchase.
Instead of just poking someone on Facebook when it's their birthday, send them the Arborwiki birthday deals list. They'll appreciate you for it (and they might bring you along on a two-for-one special if you're particularly lucky).