Do a group donation quilt. Have everyone bring in/contribute 3 (5" or 10" but everyones the same) pieces of fabric, show them all how to do a 10-minute block and put the quilt together for charity. Everyone can stitch together a row, another can do the border, another the binding.
At the same time, it is a learning experience so people can see how the block is done, how it's sewn into rows (with or without sashing), bordered and bound.
Make Pincushions, everyone loves pincushions. Or a threadcatcher which is something that everyone can use, especially if they're sewing outside their home and can't leave a mess. there's a ton of directions online.