Letter signs (A-B-C…) posted in each discussion area (easel stands and/or easel pads in those areas if possible -- and if it is a very large venue such as a hotel, signage -- including directional arrows -- directing participants to break out rooms, and letter signs on / in each break out room)

Long blank agenda wall with rolls of tape nearby; extra Post-Its nearby if these are being used

Time-Space matrix placed either to one side of the agenda wall or along the whole of the agenda wall: This grid can either be laid out directly on the wall with something such as masking tape (and people place their topic signs in the boxes created by this tape grid) or pre-placed on a sheet of butcher paper which will then be posted on the wall to one side of the agenda wall. Be prepared to put up a grid for all the days and their sessions, if you are continuing your Open Space into the next day.

Registration tables with contacts sheets for people to check, add, and/or change their information

Refreshments area for food, beverages and utensils (ideally, in the main room -- break out rooms can have pitchers of water and glasses)

Paper notes-taker templates available by each discussion area plus some by agenda wall or some other accessible location; also in each of these areas perhaps some blank paper for additional writing, some pens and a few markers