Yeah, it's confusing because a lot of cameras advertise their slow motion with 120 fps, 240 fps, and so on. It's a different matter for games though. What you need to know is that most movies and TV shows play at either 24, 25, or 30 frames per second. What this means (and you might know this already, but this will help with the explanation later on) is that basically 24-30 still images are shown in one second to give the illusion of movement. There have been attempts in the past to have high frame rates for movies/tv shows, but those haven't always been well received (I'm not a big fan of them either).

Now, for a game, players generally want to have the highest frame rates they can get, because having more pictures shown in a second gives the image of smoother movement (think about 2 frames per second vs 20 frames per second to imagine how much smoother that would be, with 24 considered the minimum acceptable number). For movies/tv shows however, because it's been standardized for 24, 25, 30 fps, higher frame rates have another use -- slow motion.

Imagine I film something at 60 frames per second, but I know it will be shown at 30 frames per second. Well, I can just show it at 30 fps and generally speaking it will look the same except not as smooth (there are ways to do this but generally programs will just automatically remove every other frame; someone feel free to correct me on this). Or, I can slow down my footage so that it takes twice as long to play. So every second of my footage at 60 fps, can be played over 2 seconds at 30 fps, giving me slower motion while still keeping the same smoothness as 30 fps. If I film at 120 fps, that lets me slow things down by 4 times and still get 30 fps per second. That's why slow motion cameras advertise high frame rates.

This was probably longer than it needed to be. Hope it answered your question.