Obviously, 8 minutes are by far not enough to create pieces of art. Instead, the idea is to be fast and messy by using the skills of every team member. The purpose is to generate a lot of ideas, ideally also very divergent ideas. Often, fat marker sketches (as also described in Shape Up) are used, sometimes just some verbal description or whatever might help to bring an idea across.
The following is a great team exercise but can also be used when working on your own, just to generate and capture as many ideas as possible. We actually include sketching and (dot-)voting below because we believe these are natural ways to utilize the ideas generated during the initial eight minutes:
Make sure that everybody in the team knows about the exact problem to address and is fully focused on the exercise.
Provide pens and colored sticky dots, but most importantly plenty of sheets of paper in standard A4 size. Fold the paper 3 times, so that when unfolding again, it has 8 panels to sketch in.
Assign somebody in the team to act as the timekeeper so that the team sticks to the crazy 8 minutes. Then start the timer.
Every team member, on their own, quickly sketches various ideas on how to tackle the given problem. Again, it’s not about perfection but rather the goal is to create, in roughly one minute per sketch, 8 different approaches. This could be a fat marker sketch of a screen, a sketch of a user flow, or some copywriting.
The timekeeper could give some indications about timing now and then so that a new idea is started roughly every minute. But it is more important to stick to the overall 8 minutes for the entire exercise.
If you want, you can already share some ideas in the team and gather some feedback. This is up to you. If you want, you can also keep these fast and messy ideas among yourself.
Now each team member selects one idea that appears to be most promising and refines it. So narrow down, add details, and be more specific on that idea.
What we actually have found useful: repeat the above folding exercise but use the panels now to describe a user journey in storyboard format. You might not need all 8 panels, oftentimes just 3 or 4 will be sufficient.
Once everybody is ready with their sketches, they will be shared with the entire team. Sometimes this is even done in an anonymous fashion to avoid, e.g., prejudice because team members want to please the boss. Hence, it is important that these sketches are thought out, self explanatory, and easy to understand without any explanations.
All team members will look at all sketches.
Finally, to select the most promising solution, dot voting is a handy tool: Give each team member a number of votes, say 3 or 5, and let them vote all sketches without judging. More often than not, the best idea will quickly stand out from the rest.