Dutch brewer Grolsch is mixing fun and responsibility with an iPhone game being promoted on site at a range of music festivals across Europe.

The Grolsch campaign to promote the iPhone application includes on-site calls-to-action at the point-of-sale, as well as Grolsch representatives at the events showing people how to download the application and getting people to use it, encouraging them to attempt to walk in a straight line while holding their iPhone. The marketing team took pictures at a Grolsch-branded swing-top bar with festival-goers and suggested water for the more inebriated attendees.

?They needed to convey the message of enjoying Grolsch responsibly to young drinkers at festivals this summer, and that?s a tough message for people to listen to, because it can come across as preachy,? said Jon Carney, CEO of Marvellous, London.

?For Groslch to be relevant with that message, we created an iPhone application called Walk the Line, which tells you how inebriated you are, using the handset?s internal accelerometer to judge how steady your hand is,? he said.

?Those who did well were given the chance to take a photo at the Grolsch bar, but those who didn?t do so well were told, ?Maybe it?s not time to enjoy so much Grolsch, maybe you?d like some water.?

Grolsch Brewery is a Dutch beer producer founded in 1615. In 1895 the Family de Groen bought the brewery, and it held a significant stake until 2007. It is currently located in Enschede and has been a part of the SABMiller group since 2008.

Grolsch tapped Marvellous for the creation of the iPhone application.

While on-site marketing teams are focusing on Dutch events, the Walk the Line application is available as a free download in the App Store worldwide, including in the United States.

The Walk the Line campaign debuted at the North Sea Jazz Festival in the Netherlands, which featured B.B. King, Herbie Hancock and Lang Lang, James Taylor, Jamie Cullum, Burt Bacharach, the McCoy Tyner Trio featuring Bill Frisell, the John Scofield Piety Street Band and the Anthony Braxton Diamond Curtain Wall Trio.

Grolsch has also been promoting the application at other popular music festivals in the Netherlands.

The Grolsch team encourages festival attendees to share the application with their friends to promote viral word-of-mouth.

The target demographic of the campaign is music fans of legal drinking age, which in the Netherlands is 18-plus, with a particular focus on consumers in their mid-20s.

?Walk the Line is a social application, and it?s a fun way to get that message of responsible drinking across,? Mr. Carney said. ?It?s not preachy.

?One in five friends in that target demographic of mid-20s and up will have access to an iPhone,? he said.