Another expression taken from comic book charcters this time is said when a couple of folks pal around all the time or just mesh in chemistry..."like Mutt and Jeff" or "they're a real Mutt and Jeff" or "here comes Mutt and Jeff". It somehow implies that the duo has a humorous quirk to their friendship, or sometimes even an unlikely pair.

Wonder if this one'll appear this week?

Here's a Mutt and Jeff comic/history site:
http://www.the-forum.com/ephemera/mutt.htm