Once game begins, players may pick up only one item of clothing at a time, fold it, and then add it to their pile to be counted once all items have been folded. In cases where more than one item is to be folded together, e.g. socks, player must retain first item until match can be made. If a player inadvertently picks up multiple items, they must all be folded and then given to player on their left.
Game ends when all items are folded.
Gosh, it's harder to write up game rules than I expected--there's probably at least one goof that I missed. Feel free to share any variations or improvements--this is just something I came up with this morning while folding my own laundry (alone, alas!).