Starbucks, Caribou offer free Earth Day coffee

April 22, 2011 8:16:09 AM PDT
It's Earth Day, and for at least two coffee chains that means a free cup of joe.

Coffee giants Starbucks and Caribou are among the retailers offering freebies and special on Earth Day.

Both are giving away free coffee to customers -- the one catch, you need to bring in your own mug.