I had some videos I wanted to save but couldn't download. I opted to do a screen recording of a window and OBS came in quite handy here.
I installed OBS and then played around with the options and it was quite simple. The UI itself was good enough that I was able to get the videos I wanted.
I'm sure I could read the manual and do it better but I was surprised at how easy OBS made it to simply record a specific window with the video and the audio.