Sat last night in front of the TV, my fingers started itching to tackle the ball of recycled yarn I made the other day. So I grabbed the ball and a size 10 crochet hook and started messing around with the yarn, and it grew organically into a bag. Almost by itself - and I do stress the almost.
I will have to have a bit of a think before writing up the pattern and try to remember how it goes but it is based purely on how much yarn you have as the basis of this idea was to use recycled fabric.
Obviously the kittens loved it and as the bag took shape I was constantly fighting them off because they were both treating it as their personal sleeping bags.