For every restaurant that posted their menu online, I have linked to it below. Restaurants not listed did not post Chef Week reference. Some places probably let you make a 3 course meal from the regular menu, but you'd have to check. I will be celebrating Chef Week tonight at Sepia (I have never been). I don't want to single out any one place, but since I ate at Mercadito for New Years, I couldn't help but notice they again offer a steal of a meal for $30. Enjoy your meal.
Official Website Chicago Chef Week
Fultons on the River
Hearty (News Section)