Hot Sheet allows you to feature posts in your sidebar up to an specific date.
Hot Sheet is a widget for WordPress that allows you to feature specific posts in your sidebar or other widget areas up to an easily configured date. After that date, they simply fall off. If all posts are allowed to expire, the widget hides itself until more posts are added.
It adds a Hot Sheet box to the add/edit post page. If you want a post to appear on the Hot Sheet, enter the date it should display until (e.g. 12/25/2010). Hot Sheet will find all the posts with unexpired dates and display them in date-increasing order.
You can also customize the widget title to better integrate into your website.