I bought a really nice kid-size sleeping bag at Goodwill for exactly that issue while camping. I zip up just the lower portion to make a leg sack and pull it on while I'm sitting. The unzipped top half makes a nice front-robe. Because it's Goodwill, I don't worry about getting it dirty, full of pet hair, etc. It just happened to catch my eye because it had sort of an aquatic color scheme, but now I know to do it, I'm looking for a second one for the house. Maybe a third for upstairs, where I have a can't-sleep chair that sits in a cool, dark room that encourages the sleepies to return.

Kid bags are usually less thick, heavy, etc. than adult ones, so they roll up into a less bulky roll for storage when not in use, they launder and dry fast, etc. Now they do have a cotton-poly liner usually, so just get some cheap cotton flannel and pin in a liner or heck, if you get ambitious, tack it in with a few stitches.

My other camping fix is just a 6' length of flannel that wraps around head, or legs, or shoulders, or.....

For hockey I have a synthetic fleece lap blanket.... prices vary hugely, but the $5 ones I stitched into a big ole house poncho are as cushy as the small $45 one I bought at the game.

~Susan