When Joe Scarborough wondered out loud "how many times can you set your hair on fire?" before viewers stop being shocked, you might have thought he was talking about Keith Olbermann, the man whose scenery-chewing soliloquies inspired an instant-classic Saturday Night Live skit. But no, Joe was speaking of Glenn Beck. Perhaps the shot Scarborough took at Ed Schultz a couple weeks ago exhausted his monthly quota of internecine MSNBC insults. On today's Morning Joe, Mika Brzezinski and Joe took turns ripping Beck's promotion of the rally at the Lincoln Memorial he's staging Saturday on the anniversary of Martin Luther...