I was just thinking....You may be aware that Google recently updated its Adsense TOS. You can now add Adsense to 404 pages!
I thought this was kinda funny with the current indexing/deindexing issues so I modified my 404 page to take advantage of this and I recommend you do the same to recoup some losses. You can review my page by going to...well...
http://www.top-affiliate.com/busted LOL.