TeX provides the day, month, and year as numeric quantities (unless your TeX implementation is woefully deficient). Eplain provides some control sequences to make them a little more friendly to humans.
\monthname
produces the name of the current month, abbreviated to three letters.
\fullmonthname
produces the name of the current month, unabbreviated (in English).
\timestring
produces the current time, as in `1:14 p.m.'
\timestamp
produces the current date and time, as in `23 Apr 64 1:14 p.m.'.
(Except the spacing is slightly different.)
\today
produces the current date, as in `23 April 1964'.