One is the Loneliest Number

I was straightening up the living room last night, picking up Peyton�s shoes, toys and what nots, when I came across one lonely sock that does not belong to us. I am positive that this sock does not belong at my house because it sports a yellow trim and I would not let my son wear a sock with a bright yellow trim on it.

I am so confused. Where did this sock come from and why is it on my living room floor?