Great question! Ummmm, here’s an idea off the top of my head…
Set up a whiteboard that everyone must pass on their way into work in the morning. Before sitting down at their desk they must stop and write down an idea for the company. Good or bad, pretty or ugly — everything counts.
Encourage employees to take a 10 minute break during the day to go ponder ideas left by others.
I’m willing to bet that more than 50% of employees at most any company would be horrified by this requirement. The fear of “looking dumb” is pervasive.
The first day will be hard for some people, but magically, each day gets easier as they realize bad ideas don’t result in judgement, expulsion, shame, death ;)