TV series, podcasts, music, films. That's quite broad, but for example I watched all of Lost a couple of years ago while painting nids, listened to every Ricky Gervais radio show/podcast, Breaking Bad... I'm struggling to remember now because I haven't been able to paint for a while. I like 40k podcasts too.
Generally stuff that takes hours and hours to work through so I'm not spending time thinking of what to watch next and can instantly jump from one episode to the next and not waste time when I could be painting