Robert Cottingham's An American Alphabet is a series of photorealistic lithographs of the alphabet. He finds array of letters from neon signs in the city.
Mel Bochner's Language is Not Transparent is another series that I've seen before and again at the 2010 and 2011 Fair. These prints are low reliefs with MASSIVE amounts of paint that tempt you to touch it. I wish I had a camera because straight on shots of these prints don't show the depth of these rounded san serifs. Yesterday, I saw a toddler who was about less than an inch away from touching the print until her father rushed to pick her up. She cried.
Finally, Matt Mullican's Truth and Beauty series contains beautifully handwritten lettering and decorative mark making.