Early-afternoon onwards, Mikage can be found hanging out around the central plaza, dressed from head to toe in a charming gentleman's outfit and distributing these lovely fliers. He's making the most of it, too- giving his "performance" with quite the dramatic flair and far more enthusiasm than is probably healthy.
...Also he keeps licking the rose when he's bored/distracted. Living with Labrador has its perks.
Additionally, there are strange markings carved into the ground all over the paths in the vicinity of the plaza, leading towards where Mikage is standing. The markings are about half an inch deep, probably unreadable, and look sort of like this, only in the ground itself, obviously. 07-Ghost characters will be able to read the writing as "Spreading Excitement all Over the World with Haruki Suzumiya Brigade" with the emphasized letters.
Bother him! Pass him by! Get harassed! JOIN THE BRIGADE OR WATCH HIM DIE TRYING TO RECRUIT YOU