The Jargon File (version 4.4.7, 29 Dec 2003):

field circus
 n.

    [a derogatory pun on ?field service?] The field service organization of any
    hardware manufacturer, but originally DEC. There is an entire genre of
    jokes about field circus engineers:


    Q: How can you recognize a field circus engineer
       with a flat tire?
    A: He's changing one tire at a time to see which one is flat.

    Q: How can you recognize a field circus engineer
       who is out of gas?
    A: He's changing one tire at a time to see which one is flat.

    Q: How can you tell it's your field circus engineer?
    A: The spare is flat, too.

    [See Easter egging for additional insight on these jokes.]

    There is also the ?Field Circus Cheer? (from the old plan file for DEC on
    MIT-AI):


    Maynard! Maynard!
    Don't mess with us!
    We're mean and we're tough!
    If you get us confused
    We'll screw up your stuff.

    (DEC's service HQ, still extant under the HP regime, is located in Maynard,
    Massachusetts.)


The Free On-line Dictionary of Computing (30 December 2018):

field circus

   A derogatory pun on "field service".  The field service
   organisation of any hardware manufacturer, but especially
   DEC.  There is an entire genre of jokes about DEC field
   circus engineers:

   Q: How can you recognise a DEC field circus engineer with a
   flat tire?

   A: He's changing one tire at a time to see which one is flat.

   Q: How can you recognise a DEC field circus engineer who is
   out of gas?

   A: He's changing one tire at a time to see which one is flat.

   See Easter egging for additional insight on these jokes.

   There is also the "Field Circus Cheer" (from the plan file
   for DEC on MIT-AI):

    Maynard! Maynard!
    Don't mess with us!
    We're mean and we're tough!
    If you get us confused
    We'll screw up your stuff.

   (DEC's service HQ is located in Maynard, Massachusetts).

   [Jargon File]

   (1994-12-01)