Beginning on June 12, many Chicago-area fans of legendary talk show host and comedian Conan O’Brien received the opportunity to take home a commemorative t-shirt obtained from mystery vending machines randomly scattered throughout the city. The exact location of the machines is kept a mystery, but viewers of Conan’s TBS show are urged to keep on the lookout for them. The promotion is a part of O’Brien’s four-day long event called ‘Chicago Week.’

Viewers of the show tuning in at the show’s usual 10 p.m. time were given special on-screen codes to punch into any one of the machines for a prize. A total of eight different fan-made shirt designs were distributed to the various machines. It is estimated that roughly 1,500 prizes will have been given out by the end of the promotion on June 14.

While exact locations of the machine are not known, rumors claim that they have been spotted near Wrigley Field, the Chicago Theatre, Union Station and even Navy Pier. This is certainly one of the most unique and interesting television stunts performed in recent times. If you are in the general Chicago area, there is a good chance that you could luck out and spot one of these crazy shirt-dispensing machines.