Seven hours before the doors to Chicago's "Obamapalooza" open wide, I swung by the entrance at the intersection of Michigan and Congress to see how many people are assembled.  There are two lines extending north and south from the well-guarded gates.  While I'm terrible at estimating crowd size, I will say it's a pretty relaxed affair.  Folks of all ages are present, but the current crowd is heavily made up of students.  Most are sitting on the curb -- reading, chatting, listening to music.  Lots of curious, international media are hovering around and interviewing those in line.  The police plan to let the two lines curve onto Michigan Ave. in opposite directions and extend as far as necessary.  I wouldn't be surprised if it's half a mile long in both directions by the time 8:30 rolls around.