Mindfulness meditation is not unlike that, but the thing you get engrossed in is your entire mental experience: sounds, smells, the feeling of the air on your skin, even your thoughts (though you're supposed to let them go as soon as you notice them). It's a very different feeling than being engrossed in some single thing to the point where you lose track of everything else. It's more like being engrossed in _everything_ to the point that you lose track of all of the noise that's usually going on in your head, and on a good day, even your sense of self.

Also, most forms of meditation are very soothing and tend to get you into a hyper-relaxed state that you don't get from most hobbies, though I'm sure it can happen with some hobbies, like gardening.