(( The panel is a chart.  Months are arrayed down the first column, the second and third columns show sports, with the divisions in partial months rather than lined up with the ends of months. ))
Which sport are they arguing about?
-My cheat sheet-

(( The second column, reproduced using approximate dates. ))
US:
Football [[ovoid ball drawn in brackets]]: Jan 1 - February 10
Basketball: February 10 - April 20
Baseball: April 20 - May 25
Basketball: May 25 - June 15
Baseball: June 15 - August 20
Football [[ovoid]]: August 20 - October 5
Baseball: October 5 - October 20
Football [[ovoid]]: October 20 - December 31

((  The third column, reproduced using approximate dates. ))
non-US:
Football [[truncated icosahedron, 20 hexagons and 12 pentagons]]: Jan 1 - December 31

{{Title text: I would subscribe to a Twitter feed that supplied you with one reasonable sports opinion per day, like 'The Red Sox can't make the playoffs (championship games), but in last night's game their win seriously damaged the chances of the Yankees (longstanding rival team).'}}