Interesting garbage collector.
http://www.mozilla.org/projects/ef/techdocs/design/gc.html
Here is something that the BSCAL VM could do 10 years ago.. and the Cupid set-top repair network file system could do in 1997.. 🙂
http://slashdot.org/article.pl?sid=04/07/08/1324225&mode=thread&tid=126&tid=185