Hello,
last year Adrien Peulvast and I discussed the potential of a "special interest group" for simulations of systems using Tcl. The Wiki page
http://wiki.tcl.tk/49324 contains further details. Note that the systems we envisage are quite general - natural, social or technical, it does not matter.
I invite you to join us if you are interested in participating (in any way you see fit) by putting your name in the Wiki page. We are currently in the very early stages, merely formulating ideas, thinking about the way to organise it, etc.
Regards,
Arjen