With that in mind I cobbled together a load of stuff that they could sew/weave, without maiming themselves or each other. Lots of this stuff was found in Goodwill and Savers, but a lot was also random stuff from around the house. The lovely wooden teddy/fish/dog threading panels were a present from one of our friends back in the UK. The plastic punnets that you get berries in work well too for weaving and a random odd jelly shoe (no idea where the other one got to). Bits of rags, shoe laces, ribbons, pipe cleaners. It all fits nicely in the plastic tote, that can also be woven (50c from Goodwill! I love Goodwill).
It's been a big hit and a really really cheap present for them that they can play with together. I was going to save it for Christmas, but we've had 2 weeks of illness in our house and quiet time play things were badly needed.