Writing the Unspeakable
Write down what you can never ever say out loud
Source: Unknown, via Vanessa
Do you suspect that unspoken taboos are holding back the team? Consider this silent activity: Stress confidentiality ('What happens in Vegas stays in Vegas') and announce that all notes of this activity will be destroyed in the end. Only afterwards hand out a piece of paper to each participant to write down the biggest unspoken taboo in the company.
When everyone's done, they pass their paper to their left-hand neighbors. The neighbors read and may add comments. Papers are passed on and on until they return to their authors. One last read. Then all pages are ceremoniously shredded or (if you're outside) burned.