Incrementing date change

I am not really sure how to search for this, so I apologize if this is mentioned somewhere.

I know if you type todays date, then drag the little box down the date will incrementally change to the next day, then the following, etc...

Is there a way to have the increments by 66 cells (or any # cells, therefore)? So I have 66 cells that say 5/1/2010, and I would like to have the next 66 say 5/2/2010, etc. and if there is an easier way then dragging down the last 5/1/2010 to make 5/2/2010 (e.g. cell 66 to 67) and then copy/paste to the next 65 cells, I would really appreciate to find out.

Thank you for any possible feedback.