I had a chance this past Monday to meet Dr Robert Zubrin talking about his new book "Entering Space: creating a spacefaring civilization". He is also the author of "The Case For Mars", and the Mars-Direct plan which NASA has now adopted/adapted as the new plan for Mars missions.
I found him to be a very interesting speaker, and writer, and would definitely call him extropian.
The Mars society has chapters in almost every state and many other countries, I will be at the next meeting of the Chicago Chapter.
Space bound extropians may want to check it out.
Member, Extropy Institute, www.extropy.org
Life Extension Foundation, www.lef.org
National Rifle Association, www.nra.org, 1.800.672.3888 Mars Society, www.marssociety.org
Ameritech Data Center Chicago, IL, Local 134 I.B.E.W