I was at Two Bros. for the tour and a few rounds yesterday and this was mentioned. Info taken from knaves.org:
The AHA's Big Brew Day. Homebrewers across the country get together to brew beer today, because we can. This year Two Brothers Brewery has once again offered us a great opportunity. They will mash a light-colored wort of around 17° Plato (1.070 OG) for us in the new brewery's mash tun. Participants will get 5 gallons to finish as they please. Bring your own burners, kettles, wort chillers, racking equipment, carboys, and anything else you'll need. Steep with specialty grains, add extract if you like, and add your own hops. You can arrive for mash-in at 9:00am, or show up around 11:00am to set up for your boil. Everyone must be done by 5:00pm. Homebrew is welcome, and Two Brothers Beer can be purchased. Two Brothers is co-located with the Brewers Coop at 30W315 Calumet Ave. in Warrenville; map here. For more details, contact Rodney Kibzey.