Projection-based mixed reality (PBMR) which seamlessly merges physical world and virtual content has a great potential to realize various interactive systems in which users can intuitively interact with existent objects that are augmented by projected imagery. Prominent advantages of PBMR are that the users do not have to wear any annoying head-mounted displays and that augmented reality experiences can be simultaneously shared among co-located multiple users. Our group at Osaka University has been focusing on exploring broad range of PBMR interactive applications including a real object painting with projected texture (1999-), supporting of tele-existence collaboration (1999-), wearable projector to support private activities (2001-), supporting of artwork creation through heat phenomena (2002-), radiometric compensation of projection light (2002-), virtual shape deformation to support product design (2003-), interactive palmtop display (2005-), document search on physical desktop (2006-) and in bookshelf (2008-), and cooperative distributed projection (2008-). I will give an overview of the above projects to introduce our research activities as well as PBMR's promising possibilities in interactive applications.