The aim of the thesis is to investigate what leadership and organizational practices are used by companies to foster and solicit creativity and innovation trough emplyees participation. The focus will be on special internal innovation projects such as contests, hakatons, idea boxes, percentage-of-working-time policy, gamification, shark tanks, innovation labs etc. and in particular the practices used by formal and informal leaders to lead these innovation activites. The result of the research can help companies to answer questions such as: – how to motivate and retain innovative people with different profiles – how to foster creativity and innovation at all levels though partcipative organizational models – how to successfully organize different innovative events and capture positive effects from them.