Here's a super easy pattern for footies. It's shown for a woman, but just make it about an inch longer and make the seam narrower for a man. I haven't quite finished the 2nd one, yet, so I'm not sure if one skein will be enough for a larger size. Better buy 2 to be sure.
I did make my husband a pair from the "Variations" page, but that was before I developed the simpler style. These are all more like slipper socks than real slippers, however.