Which Open Source Projects Are -Really- Collaborative?

An Anonymous Coward asks: "I'm a highly competent and occasionally respected software engineer, who has worked on several Open Source/Free Software projects; some of my code is in the Linux kernel. Within the OSS community, we maintain that the main point of publicly announcing OSS projects is to invite programmers to join the project and collaborate to make better software. But in about 90% of cases, I've found that publicly announced projects in development are not actually open to new members - the project leaders will ignore unsolicited code, won't respond to emailed queries or suggestions, and in many cases the projects in question remain in an early stage of development forever." What projects do you know of that don't make an issue out of incorporating user submitted patches and design changes, and what projects put forth huge restrictions on such submissions, even to the point of not accepting them at all? "This happens even when the project has explicitly asked for collaboration, and it happens when the project leaders are big names in the OSS community as well as when they're relative unknowns. So my question is, who actually collaborates? Which projects make unsolicited development effort worthwhile by making it part of something bigger?"