Steve Benen highlights what he calls (and Kevin Drum agrees) an accusation by a Member of Congress that the President of the United States is committing treason. This reminds me that the big day is hear for my impeachment prediction: I took Bachmann, April 15, 2010. I think I'll declare that once the date passes, she's once again available with a new date (hey, I love setting arbitrary rules!). I declare myself a loser, though, and I won't try another Member.
Obviously the specific choices are wild guesses. The general topic isn't, and it's not a joke, either. I do think that a Republican-controlled House has a very strong chance of impeaching Barack Obama -- not just filing charges, which any back-bencher can do, but actually going through with hearings, a committee vote, and a vote by the full House. I could probably come up with a formula for how likely I think it is...something like 10% chance per year that Obama is president and the GOP controls the House (so a 60% chance if they have six years of that situation), with a larger majority yielding higher odds for impeachment.
I will say that many Republicans predicted that the Democrats would impeach Bush if they controlled the House in 2007-2008, and that didn't pan out. I'm not sure whether that means that the party of the president overestimates the chances of impeachment, or that Republicans just assume that impeachment is what you're supposed to do if you strongly oppose the president and you have the votes. You know what I think.