My friends got up on the dancefloor, the DJ announced "the groom has been having dance lessons for months to prepare for this", then the groom stood behind the bride, put his hands on her hips... and the conga blared out!
It was a really posh wedding and they'd hired the entire stately home we all stayed at. We congaed up and down stairs and round all the drawing rooms, ballroom etc. It was a great ice-breaker as the chain of over 100 people kept meeting each other as we danced around and looped back on each other - great way to meet the aunts, uncles and friends - and summed up my friends as the wonderfully warm people they are - with a great sense of humour. We still talk about it now...