via TwitterA sign seen during a protest by the Chicago Teachers Union.The strike going on in Chicago is serious: 350,000 students are locked out and we brought you the news in a post from this morning.We'll get back to real news in a little. First, here's a bit of levity:There is a picture from the picket lines on Monday that had Daniel Strauss, who tweeted it, saying, "Civility has disappeared in Chicago Teachers Union protests."The sign was written in all caps: "RAHM EMANUEL LIKES NICKELBACK."Nickelback, if you're not of that persuasion, is a popular Canadian rock band, which is not...