Ditto on that one boy did i feel stupid

A pan of brownies, a bag of chocolates, a bag of tangerines, basically anything easy and share-able. Bottled water, your sack lunches unless that stuff is provided.
Take two or three UFO's to work on and the things needed to finish them. That way if you get tired of working on one or get it finished you'll have something else to do.

Small baggie to tape to the table for garbage (unless you have a little tidy tote with a pin cushion
Show and Tell, Name Tag, handwork, book, Masking Tape
Camera and batteries, and recharger and chair.
Commuter mug
Paper scissors, snips & fabric scissors and seam ripper.
Post its
Notepad & pen/pencil (pigma pen for labels)
blue disappearing pen, yellow or white chalk marker, extra fabric in case you want to make something else?
Fabric for projects you are working on. Batting
Sewing machine (including your foot pedal & power cord, manual, 1/4 inch foot, walking foot, free motion foot, screwdriver)
loaded bobbins
new blade for rotary cutter
Threads for piecing and quilting.
Ott-light, magnet,
Stabilizer (newsprint or tissue), heat n’bond lite, freezer paper
Safety pins, straight pins, basting spray, thread catcher
Wrist brace
Design wall

I would take a package of machine needles in case you break more than one. Hope that doesn't happen, but you never know. Bottled water and snacks are good too. Also take several spools of thread in your color choices. You may also want to take some hand sewing needles and a thimble if you plan to finish your binding by hand. That way you just might come home with some truly "finished" objects.