Fred Wright wrote:
> As I recall, this was a poster/sign hung by a computer
 > (mainframe) room window in the (now) Johnson Spaceflight
 > Center many years ago.  ...

If you search Google for "gefingerpoken blinkenlights"
you'll get lots of hits.  This version is supposed to
be the original:

  http://www.tuxedo.org/~esr/jargon/html/entry/blinkenlights.html

         ACHTUNG! ALLES LOOKENSPEEPERS!

    Das computermachine ist nicht fuer gefingerpoken
    und mittengrabben.  Ist easy schnappen der springenwerk,
    blowenfusen und poppencorken mit spitzensparken.  Ist
    nicht fuer gewerken bei das dumpkopfen. Das rubbernecken
    sichtseeren keepen das cotten-pickenen hans in das
    pockets muss; relaxen und watchen das blinkenlichten.

This version uses "blinkenlights":
   http://zork.net/1997/blinken.html

I first saw a sign like this at the (interior) window
to a lab in the business school at Penn State where the
"IBM Machines" resided, with their many blinkenlights.
This was in 1963.  In fact, this was really my first
exposure to these impressive machines, looking so cool
and scientific in their clean, glass-walled enclosures.
And just think, some of these beasts were even more
powerful than a TRX-80!

I was a journalism student at the time, not yet having
seen the light -- nor the small paychecks I would get as
a reporter!  Not that I'm making a lot more than that
now, but that's not important right now . . .

The business school also had powerful machines that could,
in a whirlwind of activity, sort a thick deck of punched
cards on any column you chose, and with multiple passes
you could sort on multiple columns.  Remarkable.

The computer wizards even had a computer dating party,
and at least I was matched with someone compatible enough
for an hour's enjoyable conversation ...    ;-)

Vic