Be advised, it's now summertime. So when stuck in conversation with someone with whom you have nothing to say, instead of "Cold enough for ya?" you should proceed with the alternate, "Hot enough for ya?" until further notice. Yes, it's that wonderful time of year again here in Chicago when everyone looks sweaty all the time and everybody seems to have Friday off except you. In no part of the city is that more true than downtown. But if for some reason you're still not sure if it's summer (like say, the temperature drops 30 degrees overnight, for instance), here are ten things to look for around the Loop that should tip you off.