<p>What does the expression "Turing Complete" mean? </p>

<p>Can you give a simple explanation, without going into too many theoretical details?</p>

From
wikipedia
:
Turing completeness, named after Alan
  Turing, is significant in that every
  plausible design for a computing
  device so far advanced can be emulated
  by a universal Turing machine — an
  observation that has become known as
  the Church-Turing thesis. Thus, a
  machine that can act as a universal
  Turing machine can, in principle,
  perform any calculation that any other
  programmable computer is capable of.
  However, this has nothing to do with
  the effort required to write a program
  for the machine, the time it may take
  for the machine to perform the
  calculation, or any abilities the
  machine may possess that are unrelated
  to computation.
While truly Turing-complete machines
  are very likely physically impossible,
  as they require unlimited storage,
  Turing completeness is often loosely
  attributed to physical machines or
  programming languages that would be
  universal if they had unlimited
  storage. All modern computers are
  Turing-complete in this sense.
I don't know how you can be more non-technical than that except by saying "turing complete means 'able to answer computable problem given enough time and space'".