A Leap Day Rabbit Trail
We are very fond of rabbit trails. We're studying Ancient Rome, and just learned that Julius Caesar first proclaimed the last day of February as Leap Year Day in 45BC. Back then, February 30th was the last day of the last month of the year, which is why he picked it.
Then, in 4 AD, Emperor Caesar Augustus corrected a counting error in Leap Years. He also got the month of August named after him, and stole the last day of February so that August could have 31 days, just like Julius' month.
By 1582, Pope Gregory XIII recognized that Easter would eventually occur closer and closer to Christmas. The calendar was altered so that a leap day would occur in any year that is divisible by 4 but not divisible by 100 except when the year is divisible by 400. 1600 and 2000, although century marks, have a Leap Day.
This just begs for a special one-day mini unit. Check this out for more than you can possibly do in one day! The link says it's math, and it is, but it's also a LOT more!
If we end up with a lapbook, I'll post it.