Cruise Celebrity Cruises extends Wave promotion By Tom Stieghorst / April 16, 2013 Share 1 -- Celebrity Cruises said it would extend its 123Go! promotion developed for the Wave season to summer cruises that are booked by April 30.The promotion has been cited by agents as one of the most effective and valuable booking incentives this year. It offers a choice of a complimentary drinks package, complimentary gratuities or a $300 onboard credit for reserving a Celebrity cabin.The extension applies to cruises to Europe, Alaska and Bermuda from June to September. Travelers going to Europe can choose two of the three incentives. Follow Tom Stieghorst on Twitter @tstravelweekly.