With RichDatePicker, they have a pop up with Q1, Q2, Q3 & Q4 down the left hand side of the regular year picker.
When a quarter (Q1-Q4) is selected & then a year is selected, the input field will display "Q1 2008" for example.
On the server, the first day of the quarter is returned as the SelectedDate.
An improvement would be the ability to have the first date or the last date of the quarter returned.
Then as another example, you could have two date pickers where a date range of a selected year could be returned.
e.g. QuarterStart.SelectedDate & QuarterEnd.SelectedDate
It would be very useful for business and financial apps.