In light of tomorrows date...

[kolonuk]

DEF VAR v_Date AS DATE NO-UNDO.
v_Date = DATE(MONTH(TODAY),13,YEAR(TODAY)).

REPEAT
:
    IF WEEKDAY(v_date) = 6
    THEN DISPLAY STRING(v_Date,'99/99/9999')    FORMAT 'x(10)'
                                                LABEL '"Friday the 13ths"'
                                                .
    v_Date = ADD-INTERVAL(v_Date,1,'month').
END.

Enjoy!