aureport and scripting -ts and -te?

[srehrlich-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org (Scott Ehrlich)]

I want to automate auditing scripts using aureport and would like to
have a cron job place the results of aureport incorporating -ts and
-te into a text file.   But how do I set up the dates (say each day or
for a week) in cron to pass to -ts and -te?

I might want aureport --summary -ts 02/11/2011 -te 02/18/2011 > summary.txt

Now, how to convert 02/11/2011 and 02/18/2011 to a variable format for
daily or weekly or any other period of time for cron?

Thanks.

Scott