As Multithreading, concurrent programming and similar topics sometimes are mentioned on the UT as well,
a very succinct and "down to earth" definition for asynchroneous models is the description from Bradley Meck in

http://groups.google.com/group/nodejs/browse_thread/thread/abe7483399c69727#

and the issues raised in the other posts sounded familiar from the parts I developed in vfp and Modula2 ;-)

Node.Js is a bit in the early stages as of now, but should be taken into account as soon as it sets foot on more than on mobile device and/or windoze as well. Coupled with machine-code compiled JS possibly a disruptive technology.

thomas