Yesterday I was asked if there was a simple way to group records into Spring, Summer, Fall and Winter.  There are several ways but I think this is the simplest.  I convert the month and day into a number by multiplying the month by 100 and then adding the day number.  This gives every day of the year a sortable value from 101 to 1231. Then you can use that value in a formula like this:

Local NumberVar x := Month({Orders.Order Date}) *100 + Day ({Orders.Order Date});
If x < 320 then "Winter" else
If x < 621 then "Spring" else
if x < 923 then "Summer" else
if x < 1221 then "Fall" else "Winter"