Twenty children all grinned at some shared joke.

Kathryn shook her glossy mane of curls and joined him in his shared joke, however true it was.

The parents smiled at this, like it was a shared joke between them.

He smiled at the small shared joke.

Television reporters are, after all, a widely shared joke.

There were two, laughing over a shared joke.

The smile was a shared private joke.

A group at a nearby table laughed at a shared joke.

Iqbal and Run must continued to giggle over some shared joke of long ago.

As that comment indicates, the lack of information has become something of a shared joke.