brunch in pilsen:
With no other criteria, I'd think of Mundial Cocina Mestiza, or Nuevo Leon on 18th street. I have a special place in my heart for La Casa Del Pueblo which is enhanced cafeteria style, and is open during that time, and could definitely accommodate, but is bare bones.
Mundial is fancy and worth it, Nuevo Leon is homestyle Mexican, casual - no reservations, but they might make an exception for your table size. Even if they do not take a reservation, you will be seated pretty quickly for a group of that size. Late summer last year, I set up a brunch for 8 in Pilsen on a SUnday - Mundial was my first choice - they were closed for a private party, so we went with Nuevo Leon. Decent grub, cheap, festive, bustling place. Our table of 8 (with three toddlers) was seated within ten minutes of arriving with no reservation, and the place was full.
Are you looking for some specific kind of food - or just anything? Price point?