This is along the same lines as your thought of getting ugly checks/cards. But as a sports fan, if you got the rival of your favorite team, then you would really hate using that Yankees card! Of course, the best idea for the checks is to not spend any money on them, because most banks give you free basic checks with a checking account now-a-days. There's my 2 cents.
Oddly enough, as of right now (11:00am Wed), that picture is still showing up on AOL, but Internet Explorer has one with only Nash and Dirk for the Western conference finals. Same URL and everything.