My soon-to-be alma mater has very small class sizes (student-teacher ratio is less than 10 to 1, most upper level classes are 4-8 people), so class here really is often a "conversation of peers". Discussions are an excellent way to learn, both because they encourage questioning and sharing and because they force you to engage the critically engage material on a regular basis rather than just memorizing it long enough to take a test.
People often seem to think of discussion-style teaching as being a social science/humanities thing, but it also works surprisingly well for math, computing, and science. I think a lot of people have the idea that in more technical courses, you have to do lectures (maybe with labs) because you're basically trying to teach a bunch of information. Most schools focus on teaching technical skills and knowledge, and expect you to just pick up on how to think as you go along.
Turning that around--teaching thinking and letting students pick up technical skills from examples--seems like a better idea because technical knowledge progresses so rapidly and because technical skills are easier to pick up. It also enables discussion-style teaching in math, computing, and science. Instead of listening to a lecturer spew material you could have found in a book, you solve problems together.
(Aside: interactive learning is really the only way to justify the high cost of college from an educational perspective. Ignoring stuff like networking and partying, it seems like going to a school where they teach by lecturing is a waste of time and money, since there are so many free lectures available online.)
The "everyone vote on answers" format is a surprisingly effective way to improve engagement in lectures. They get people to pay attention, they give you in-class feedback about what you have learned, they give the teacher more input (like you said), and they make lectures a bit more fun without being too cheesy.
Another simple technology-based way to improve engagement is to have students post their writing for class (reading responses, essays, etc.) on a forum. I took a class once where, instead of sending the professor a reading response for every class, we posted a reading response to a class Facebook group once a week. We were also required to write at least one substantial reply to others' posts once per week. The interaction was awkward, at first, and some people did the bare minimum the whole time, but after a few weeks a good chunk of the class was posting more than they were required to on a regular basis. Besides simply improving engagement, it seemed like it was making people think and write better, probably because they knew their peers were going to read what they wrote.