I have two...
my family is too large to buy gifts for everyone, so we tried the Dirty Santa game a couple of years. My nephew's mother-in-law and father-in-law would join our family since they only had one other daughter, and she doesn't speak to them-they don't even know where she lives. (Turns out she caught the dad having an affair, told the mom, now neither parent will acknowledge she exists).  One of the gifts they brought was a "Butt Cruncher," one of those stupid As Seen on TV exercise machines that does not work. I was unfortunate enough to get it. It would not even sell in a yard sale-had to donate it to Good Will.  
The second was the year my brother, who normally gives great presents, gave everyone a clear glass plate with a Christmas design on it. They still had the 2.99 price sticker. I was a young college student. What did I need a big ol tacky Christmas platter for??  At least that one DID sell in the yard sale! lol