Since I'm sick and laying down makes me feel like I'm drowning, have some Leap Year Legend research. Not really Winchester case material, but you never know.
"Ladies Privilege" Very old obviously. Feb 29th was the day a woman could ask a man to marry her, and if he refused, he had to pay a forfeit.
"Carberry Day" At Brown University, every Friday the 13th and February 29th is 'Carberry Day', a day when loose change is collected in ceramic pots as a donation to the library. This commemorates a hoax lecture on 'psychoceramics' by a 'Dr. Carberry' posted on May 13, 1955.
I can't believe there isn't a cool legend somewhere about a Brigadoon-style village that only shows up on Leap Years or a ghost that haunts something every 29th of February. I feel vastly cheated.