Because LJ had a major outage last week, they are offering a free week to paid members. The offer applies only to active paid accounts during the outage window from Friday (11/03/06 at 12:01am GMT) through Monday (11/06/06 ending 11:59pm GMT). The extension claim expires on Monday, 11.20.06 (at 11:59pm GMT).
See http://community.livejournal.com/paidmembers/18838.html for all the details.