The battle for the Alamo that occurred from Feb 23-Mar 6, 1836 was a leap year. Official action leading up to the March 6th finale did occur on Feb 29th. For example, Mexican's Jimenez battalion and the cavalry under command of General Ramirez y Sesma were ordered down the Goliad road to intercept any reinforcements that might have been sent by Fannin. Finding none, Sesma returned to San Antonio the next day.
Also, the Mexicans proposed a three-day armistice and several Tejanos leave Alamo during the cease-fire.
Since 1836, there have been 46 leap years.