_(Lambda calculus) is not only an abstract calculus, but an *(Abstract VM): a kind of calculus of very basic abstraction. It was invented even before Turing Machines, also as a universal computational framework. Check pages and books about functional programming, _(functional) programming languages, computer science laboratories, theoretical computer science research, etc, for more about lambda calculus.

A few pointers: 
<ul>
<li>See the series of "Lambda, The Ultimate <var>FOO</var>" articles.
In _(the original ones|http://library.readscheme.org/page1.html) by GLS, <var>FOO</var>={ _(Imperative|ftp://publications.ai.mit.edu/ai-publications/0-499/AIM-353.ps) | _(Declarative|ftp://publications.ai.mit.edu/ai-publications/0-499/AIM-379.ps) | _(Goto|ftp://publications.ai.mit.edu/ai-publications/0-499/AIM-443.ps) | _(Opcode|ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-514.pdf) }.
They are available among other classic hits from MIT AI lab publications.

<li>On the "Lambda, The Ultimate <var>FOO</var>" trend, <var>FOO</var> has also been { software tool | label | combinator |
_("little language"|http://lambda.weblogs.com/discuss/msgReader$1831) }.

<li>
This article by _(Jonathan Rees|http://mumble.net/jar/): _(W7, a security kernel based on the Lambda Calculus|ftp://publications.ai.mit.edu/ai-publications/1500-1999/AIM-1564.ps.Z), <em>could</em> have been called "Lambda, the ultimate capability".
See Rees's _(PhD Thesis|http://mumble.net/jar/pubs/secureos/).
Similarly the _(Tube) <em>could</em> have been "Lambda, the ultimate mobile code".

<li>Finally, _(James Crippen|http://www.unlambda.com/~james/)
collected fortune cookies that have the _(Lambda nature|http://www.unlambda.com/~james/lambda/lambda.txt), many of which are but exerpts from _(Alan Perlis|http://www.cs.cmu.edu/csd/perlis.html)'
_(Epigrams in Programming|http://www.cs.yale.edu/homes/perlis-alan/quotes.html)".

<li>Several programming languages have a strong basis in the lambda-calculus, including:
<ul>
<li>_(Lisp)
<li>_(ML)
<li>_(Haskell)
<li>_(Clean)
</ul>
</ul>
