My first tidbit is actually based on something I borrowed from Quick Hits. In fact, if I remember correctly, it was described by Scott Sernau, who was one of my teaching mentors at IUSB. But I adapted it to my needs.
Simply put, I let students select topics to be covered during the semester. And I find it advantageous in some contexts.
The way I do it is quite simple. During the first week of class, I distribute a list of topics and each student has to select a limited number of them. Topics with the largest numbers of votes are added to syllabus and the coursepack is built based on this selection.

I reserve the right to merge topics. So, two topics which seemed relatively unpopular may form parts of a broader topic which can reach more students. I put topics in a sequence after they’ve been selected, to avoid some bias effects on the section process. And I typically have predetermined topics for the first few weeks of class, both as a way to make sure everyone is on the same page, especoly about basic concepts, and because it gives me more time to prepare the readings for the rest of the semester.

Some things make this technique more practical. For instance, it works well in a small seminar but it’d be very hard to do in a large textbook-based class. Where I first used it (IUSB), it was possible to build the coursepack through the semester. In fact, the electronic reserve system even allowed me to bypass the coursepack format altogether. At another place where I’ve used it (Tufts), coursepacks took enough time to build that it could only be done for a later section in the semester. I had to start with prepared material before the semester started. In other cases, including Concordia, the coursepack system is such that it’d be very impractical to use this technique unless it’s possible to meet students weeks before the course starts.
I’ve noticed a number of advantages with this technique. One is that it pushes students to engage in those broad issues of course design which give them insight into the course as a whole. Not only does it mean that students are a bit less passive, but they get a behind-the-scenes look at what teaching involves and may understand diverse things about the way topics relate to one another.
A related advantage is that students can claim ownership for a dimension of the class. Even without discussing the effects of the selection process very specifically (it’s not my thing to say “you chose the topics, don’t blame me if you don’t like them”), there’s a clear sense that te course as a whole becomes a shared responsibility.
In fact, I’ve associated this with te typical seminar structure of having individual students “responsible for” individual topics. Though everyone has to understand all the topics, each student becomes more of an expert in a given topic, often doing a presentation about it. I should elaborate on this as a separate tidbit, but it’s a common format for seminars, in some contexts. The way it works with the collaborative syllabus is that people can choose, at the same time, a series of topics they want covered and a specific topic on which they want to work. I usually try to get the student’s expertise on that topic to carry through the semester, but that part hasn’t been too effective.

Yet another thing I’ve noticed with the collaborative syllabus is that the way I explain a topic may have a large role effect on how students select them. For instance, the first time I tried this method, in a seminar about linguistic anthropology, I had semiotics as a topic. When I explained it, I mentioned zoosemiotics and associated animal language with that topic. That semester, semiotics ended up being the most popular topic in the initial vote, something which I wouldn’t have expected, had I designed the syllabus by myself, without student input.