OFFENBURG, GERMANY — The black telescoping arm of the Supertechno 30 camera crane swooped over the live television audience, as the scent of pyrotechnics from a Swedish band’s performance lingered in the air. The Academy Award-winning actor Denzel Washington watched as a German man wearing goggles stuck his finger in a bottle and made a popping sound.

Mr. Washington clapped and offered encouragement as though he was back on the sidelines in “Remember the Titans.” He was urging on a young Bavarian, Bernhard Siegel, who was trying to guess from the plunking sound alone how much water was in a series of bottles, for glory, fleeting fame and the chance to win a brand-new car.

It was a recent Saturday night, and Mr. Washington, there to promote the film “Flight,” had entered the very German universe of “Wetten, Dass ...?,” a variety show with some 10 million viewers often referred to as the biggest television program in Europe. In more than three decades it has anchored itself in the German consciousness even as viewership has declined and criticism has risen, not just about the show but also about what it represents.

Something of an amalgam of “The Tonight Show,” “Saturday Night Live” and “Battle of the Network Stars,” “Wetten, Dass ...?” — which loosely translates as “Want to bet that ...?” — began in February 1981, and the format, in which everyday people compete to execute strange “bets,” or feats, has changed little. Those wacky challenges, what David Letterman might call “Stupid Human Tricks,” remain the heart of a show that is a beloved but perpetually struggling German institution.