Wheeled out on a stretcher. Remember, he was diagnosed with a malignant brain tumor in May.
Senator Byrd (D-W.Va) collapsed as well, although it doesn't sound as serious. I'm not a big fan of Byrd, being a former Klansman and all.
(Photo from earlier in today's inaugural luncheon)
UPDATE: Senator Claire McCaskill (D-Mo), who has been twittering all day, notes Kennedy's collapse.