Code (of function) that can automatically be executed Once weekly

Hi,

I'm trying to design project where users can make posts and get other users to like the post. This is actually achieved.

But the challenge I'm having is that, upon a weekly basis, Preferably Every Saturday of the week, The top 10 posts with the highest like be declared and shown in a page.

E.g:  The winners for this week's games are:

• Dgunners (100 likes)
• Power (89 likes)

Note: This should be executed every (and only) saturday @ 00.00am. This is because The result from the query will be stored in a database table e.g. tblWinners

Any code snippet, link or hint to resolving it will be most appreciated.

Thanks