If you are using Microsoft Outlook 2010, I've got a handy trick you can use to easily insert a calendar in your e-mail with the relevant dates already highlighted, courtesy of the Microsoft Outlook blog on MSDN. To inset a calendar, do this:
- Open a new message window and then click Insert, Calendar.
- In the Date Range drop down, choose Specify Dates and then select the start and end dates you desire.
- Click OK.
Want to embed the calendar in an out of office message? Just try the trick above in a blank e-mail message, copy the calendar, and then paste it in the OOF message.