Back in 2006 Clockshop, a non-profit arts and culture organization did an "artist's billboard" of a map of CIA rendition flights. I'm not sure if this was in a gallery space or if it was an actual outdoor billboard. All they give you is an address on Wilshire Blvd in Los Angeles.
One of the artists - Trevor Paglen has taken it a step further and developed a web application where you can actually view the daily flights from 2001 to the present. Click the image at right and then click the flight viewer in the upper left corner of the page - very slow load warning!
Parts of his description of the flights are worth quoting here (the rest can be found on his page):
"These private charter planes often use civilian airports for refueling, making their movements subject to public record...the nature of the program has thus far remained out of reach to both American and International law...human rights activists are left to view their movements as a vast 'black box' and can only speculate whether any specific plane is currently carrying human cargo"
15 years ago