I freakin' messed up last week concerning a BEST BUY warranty. I have an XM SkyBox (http://products.howstuffworks.com/audiophase-xm-skybox-ms-040004-review.htm).
The CD player has been broken for months now (It has AM/FM/XM/CD player). I went to take it in on Dec. 4. I looked at the warranty receipt and it expired Dec. 3. That is what I get for not double checking when it expired. I bought it in 2004 but thought it was later in December.