I did XP on a project in Sydney Australia which was a lot of fun and eXtremely successful! http://xpdx.org/files/ExtremeSuccess
I have done all kinds of software from GUI to Real-Time, including IDEs, compiler and runtime systems for dynamic languages, et cetera. I like and believe in UserCenteredDesign which fits right into Agile/XP practices.
Recent "just for fun" projects include a Scheme->Smalltalk translator (including a complex number package) and some Squeak Smalltalk "GUI for ordinary folks" prototyping. I have been implementing Ward's FIT test system in Lisp and Scheme.
I am interested in making computers usable by ordinary folks!
Email me at: Ken(dot)Dickey(at)whidbey(dot)com