A few years ago I came across the story of Patrick Combs [1] depositing a fake check for $95,000 [2] and having it actually clear but at the time he had yet to finish telling the story.
Time passed. I lost the link. Couldn't find it again, until now. I was reading the journal of Amanda Robbins [3] (who is the girlfriend of my friend Kurt, the high school English teacher turned plumber) when she linked [4] to it!
Of course, the story is now finished—he ended up giving the check back to the bank, but only after they furnished him with a latter detailing their mistake in cashing it and apologizing to him. And I suspect doing such a stunt today wouldn't work.
[2] http://www.goodthink.com/$tablecontents.html
[3] http://www.livejournal.com/users/margaretlane
[4] http://www.livejournal.com/talkpost.bml?journal=margaretlane&itemid=383704