You are welcome, sir! How about this chapter of the famous book "Practical Common Lisp", available online for free?
http://www.gigamonkeys.com/book/beyond-exception-handling-co...
googling for "common lisp condition system" turns stuff up. i looked at one point, and i don't remember finding an academic treatment of them.
they're (hand wave hand wave) basically a matter of stuffing the current continuation inside of the exception, whenever you throw an exception, and then making use of that to provide more options whenever the exception is caught.
I found this extremely weird and (or hence) interesting at the same time. Where can I read more about this?