multiple sites using one install?

[1996 328ti]

Each year one of my sites change a bit because of different events and locations.
I want to keep each yearly site for historical purposes.

Last year I moved the entire site to /2008.
http://www.bmwccaofest.org/2008
This year I will probably copy everything to a /2009 directory.

Then delete what is not needed for my 2010 site, update it and start all over.

Is there a logical suggestion to accomplish what I want to do?