Also check out the {{{time}}} macro if you want complete control on
the formatting of the date string.
Example Org snippet:
=====
#+date: {{{time(%Y-%m-%d)}}}
#+options: toc:nil author:nil
See the ~{{{time}}}~ macro in [[info:org#Macro Replacement][org#Macro
Replacement]].
The format passed to the ~time~ macro is same as that understood by
[[help:format-time-string]].
- Note :: Remember to escape the commas. \\
Example: ~#+date: {{{time(%b %e %Y\, %a)}}}~.
#+begin_src emacs-lisp
(org-export-as 'ascii)
#+end_src
=====