Laughter makes strangers temporarily forget why they were separate.

For the length of a shared laugh, everybody in the room is on the same side. All the sorting people do about status and difference goes quiet, because you cannot laugh with someone and hold them at a distance at the same time. It is one of the fastest routes into a group there is.

Be the one who notices the funny thing out loud. It is a small social risk with a large return, and it does more for a tense room or a new group than any amount of correctly chosen conversation.