Each year, on the Friday After Thanksgiving, the MIT Museum hosts a hugely collaborative Chain Reaction in which simple or complex contraptions built by participating teams are joined into one massive Rube-Goldberg-esque chain reaction viewed by over 1500 attendees.  (See videos from 2013 and 2014.)  Teams must register beforehand, pay $12 in advance or $15 at the door, and design with these guidelines.  This year, the 18th annual F.A.T. Chain Reaction will be on November 27, 1-4PM, and all contraptions should connect somehow with the theme “18th Century.”  On the day of the event, teams will bring their contraptions to the Rockwell Cage Gymansium (120 Vassar Street, Cambridge) at 11:30AM, the public can view contraptions and talk with teams 1PM-3PM, and the chain reaction will start at 3:30PM.