Originally Posted by Lycanthrope

From the docs

AGE (optional)
Use this value to specify an exact age of galleries that can appear in this section. If you are using this value, it should be a non-negative integer. For example, setting this to 2 means that the gallery must be exactly 2 days old. Valid values start from 0 (for today) and continue upwards (1,2,3,etc).

##Today## - The current day's date. You can use ##Today-1##, ##Today-2##, etc up through ##Today-9## to display dates from previous days

But it is apparent that you can only do 10 days worth. Today and the previous nine.