Agile as part of Waterfall

When we started developing with Scrum, it was just the development team using Agile, but we were one of many teams still working in a waterfall style (one long cycle with a delivery at the end). This introduced a couple of irregular circumstances when we tried to follow the Scrum process as best we could, for example we always had 2 week Sprints, starting mid week and could fit 3 sprints into the larger delivery process, but we would have a couple of extra days at either end where we couldn't start on the next delivery because the one we had finished (early) hadn't been submitted yet. 

Mixing Scrum and Kanban (Scrumban)

At my previous job, my team was part of a pilot to switch over to an Agile methodology for development. It was generally successful so we continued doing it after the pilot had ended. We started with Scrum, and did Kanban when needed, and ended up merging the two into a sort of "Scrumban" process. This was just based on our experience with the two processes as a team, and not based of any official sort of Scrumban process.