The travel firm will initially ask readers to submit holiday-related headlines to appear on the back page of Metro every Tuesday.
Readers will be able to submit their entries via the travel brand's website and the weekly winner will receive £50 of Expedia vouchers.
The activity, devised by Meteorite, will develop during the year, culminating in readers being asked to submit not only a headline but also holiday photos, recommendations and tips.
Expedia will back the initial campaign with TV and online ads. Media planning and buying for the activity has been handled by PHD.
Last December, Associated Newspapers revealed plans to boost Metro's digital presence with the launch of its first mobile service and two online portals. Metro Mobile will repackage Metro's news and showbiz content for web-enabled mobile phones.