Knitting with a kitten in the house is tricky. When he's not trying to catch the ends of my knitting needles, he's playing with the balls of yarn.
My mum taught me the solution to this problem. Pop the ball of yarn into a container with a hole cut in the lid. Mum used margarine tubs but I'm using an ice-cream tub. The tub needs to be big enough for the ball to move and unwind itself. Cut a hole in the lid and feed the end of the yarn through, then knit as usual.