The reliable test for a team building activity is whether people would choose it. Collect candidates from the team, let them react, and run whatever wins — chosen activities land better than imposed ones.
Put the candidates on a board and let reactions decide. Participation goes up sharply when people choose the activity rather than receive it.
Say how long it will take and end on time. Most resistance to team building is resistance to an open-ended calendar hole.
Anything mandatory stops being social. State clearly that skipping is fine, and more people will show up.
Short, optional and built around something real: show-and-tell, lightning talks, random pairings. Long scheduled games tend to work worse remotely than a 20-minute session with a clear end.
A small recurring slot beats a rare big event. A short monthly session that people actually attend builds more than an annual offsite game.