This is what I wore on a very lazy day around the house. I firmly believe in taking it easy as much as possible on break days. This plaid shirt is what I ended up using my last Banana Republic $10 credit on. The fit isn't amazing, but the color is good and it's comfy and warm, and hey, it was only $5.
Plaid Flannel Boyfriend Shirt in Blue/Green, Old Navy, Denim Stretch Jeans, Coldwater Creek, Fuzzy Socks, Costco.