Excel 2008 : Duplicating, then incrementating dates

I'm trying to duplicate a series of dates while incrementing by 1 every 2 rows.

For example:
January 10, 2012
January 10, 2012
January 11, 2012
January 11, 2012
January 12, 2012
January 12, 2012

I've searched high and low for an answer, but can't seem to find what I'm looking for. I know it can be done with numbers, but I can't seem to find a formula/method for dates. Hope someone can lead me in the right direction.

Thanks

One way,

Let's say the start date is in A2. So use this formula in A3, then copy down.

=A$2+INT(ROWS(A$3:A3)/2)