Message: I Jokehttp://www.slate.com/blogs/blogs/trailhead/archive/2008/11/02/message-i-joke.aspxPolitical comedy is hard. On-message political comedy is damn near impossible. But John McCain managed to pull it off on last night’s Saturday Night Live , where, with the help of Tina Fey’s Sarah Palin, he poked fun of Barack Obama’s much-viewed half-hourenCommunityServer 2.1 SP2 (Build: 61129.2)