Squeak!

Squeak is an implementation of the Smalltalk system with some very outstanding features: Most pointers to other Squeak info can be found at the UIUC Squeak Home Page, and some more at the CREATE Squeak Site.
Squeak has an active mailing list. To subscribe to the list, send a mail to squeak-request@cs.uiuc.edu with the word subscribe in it. The list is archived at the UIUC Mailing List Archives (note that the archive is quite unwieldy; probably someone would like to make it more accessible?).
Thing's I'm working on in my little spare time:
Hans-Martin