How can you know the framerate or 480p/576p/720p/1080p/1080i by just looking at it?

I mean don't use anything to measure it but only your eyes, it seems like many of you can do that but how? 

I can tell 30 vs 60 fps pretty easily, provided there's not much motion blur.

Resolution's a lot tougher, but if you get close, you can tell when the jaggies don't line up with the actual pixels. Though I can't tell much other than when something's not the native resolution of whatever screen I'm looking at.

Do you have Mario Kart Wii?
If the answer is yes then do what I tell you and you will perfectly understand the difference of fps.

☆☆☆ Choose a course and play it. What you see is 60 fps.
☆☆☆ Invite a friend, choose the same course and play in split screen. What you see now is 30 fps.

How do you know it is not 40 or 50?

From an analysis of GTA IV, it show that Xbox 360's avg framerate is 32, PS3 is 29.

Some of the people say that earlier console can easily run as 60 fps, is that true?

How about portable handheld? Is that a different method to measure them?

What is better 1080i or 720p for watching TV? My TV and satellite support both so I just put it on 1080i, but I dunno if that's the best option.

Yeah, Mario Kart is a great way to see how different it is.

However, I thought offline split screen was 60 fps, but I never tried it. I know online splitscreen is 30 fps, because I have played it, I never played offline splitscreen though.

Very very few people if any can just tell with a glance and no other information. But with information about the native resolution of the monitor/TV you can make some pretty intelligent guestimates at what it is based on bars at the edge of the screen, sometimes stretching depending on the source of the video input, and a number of other things.

Just as an example if you are watching TV and there are 2 black bars on the sides of the picture on your widescreen TV then there is a very good chance that what you're watching is 640x480.

I can tell the frame rate - differentiate even between 50hz and 60hz

But the resolution is tricky - Many Wii games look much better than some PS3 games - really you would have to see a multiplatform game, PS3 on 1 tv and Wii on another

It's not that it was easy, it's just that frame rates are not really dependant on how powerful the console is.  Frame rates really are a balance between that consoles capabilities and how much the developer throws at it to handle (or how crappy the coding is).

 I'm the complete opposite. I really can't tell the difference between framerates 30 or above, yet at a glance I can tell the difference between 480/576i, 480/576p, 720p, 1080i and 1080p. I will admit that I interlacing depends on the quality of the display and its deinterlacer, but on my screen (which isn't the greatest at deinterlacing) I have no issue.

 You also need to remember there are a large amount of people with HD tvs which while they support 1080i and maybe 1080p, their panel is only 1366x768. Given this, the difference between 720 and 1080 will be practically nothing, as the upscaling of the 720 and the downscaling of the 1080 signal will produce very minor 'artifacts' (for lack of a better word).