For some people watching a video can actually make them tired, such as reading a book, watching tv, taking a hot bath.
For me if there's an appointment, event, or something the next day, I won't sleep. I hate it, then I look like hell and I act weird.
I found ZzzQuil has worked for me. It doesn't really knock you out but it helps you fall asleep fast. Then again I guess it depends on the person, with me it works well, with my husband, not so much.
Sounds like insomnia to me, but I do it too, so I'm not sure if it's mania or not.