for non or weak sewers that you'd want to join the project, I'd go with real easy. I make quilts, but do not know how to sew, so anything tricky would be off-putting for me.
1. a nine patch in Christmas colours; if you have the time you could turn it into a Fractured 9-patch which would make it a more interesting quilt.
2. Rail Fence also in Christmas colours: red, white (or gold) and green. It could be scrap, but keep them in the same order.