Here is another one.

On a cruise last year I had lost throughout, and decided that I wanted to come in and leave a nice tip regardless.

I went to 3 card poker (with some bonus bet), bet only dealer bets, all spots, $25 per spot. Cost me $600 for the tip, it was a pretty lame performance by the dealer, but she hit one payout of $625 (plus kept the winning $25)

So the guys got $650.

My tip of $650 cost the house $50, so my tip, that I could never possibly win from, as it was all the dealers, was reported by the pitboss as a win of $50.

So I now owe taxes on the $50! (which was washed out by my losses, but that wouldn't have happened if I didn't have losses)