Design sprints are a 5-day process for solving problems through prototyping and testing ideas. Each day focuses on a different activity: understanding the problem on day 1, sketching ideas on day 2, deciding on a solution on day 3, prototyping the solution on day 4, and testing it on day 5. The goal is to generate ideas quickly and learn through creating prototypes rather than perfecting a single solution. Sprints help teams start projects in a clear direction, address difficult problems, and prevent unfocused brainstorming.