String interpolation with actual % in string

What's the right way to deal with this? ``` "Hi %s, today is %s so you get 10% OFF!" % ['Joe', 'Monday'] # => ArgumentError: malformed format string - %O ``` I can't use normal `%{keyname}` or `#{code}` because I'm parsing strings for urls and stripping them out so I can stick them back in different formats (with/without protocol, shortened, full length, etc). So the number of replacements is unknown and they don't have names. They are just an array of urls. I also tried escaping the `%`: ``` "Hi %s, today is %s so you get 10\% OFF!" % ['Joe', 'Monday'] # => ArgumentError: malformed format string - %O ``` but get the exact same result.