Outlook uses natural language to interpret dates

In case you did not already know, Outlook has some pretty clever parsing built in to date fields on Tasks and Appointments which can interpret and understand all sorts of combinations of “natural language” snippets to figure out what date you really mean. This is pretty powerful, and certainly saves reaching for the calendar widget to set up a meeting for the last Thursday of next month, or the first Monday after Christmas.

Sorry to say, Outlook does not know when your birthday is (“You look like you are opening a present! Do you want help with that?”), nor can it deal with Easter moving around every year, but otherwise it’s pretty smart.
See some examples of the sorts of text strings that Outlook will happily interpret»