no, televisions are pretty much static in the resolution and aspect ratio they display at because this is how the hardware works. 1920 pixels by 1080 pixels will always be 16:9 and 1080p. all pixels will be used when displaying an image but some may remain dark (often dark dark grey because the backlighting is still active).
now, on the input side of things, dvd players can play 4:3 content and display it on a 16:9 tv perfectly fine. you will see black bars to either side of the video. in the case of superwidescreen you will have black bars top and bottom. as long as the input device (dvd player, console, pc, laptop) is capable of playing the file in whatever aspect ratio its encoded in, it should be able to convert it for use on your tv though do expect black bars.
most tvs have stretch, zoom, fit options which cut off parts of the feed to better fit a nonstandard ratio to fit your tv. for instance when playing 4:3 content you can zoom or fit to fill the screen but you will lose the bottom and top parts of the content.
The aspect ratio is set by the proportions of the screen (4:3, 16:9 in TVs & PCs and 21.9 for PC monitors). Multiple monitors (or video tiles) can be used to create a video wall of many different aspect ratios. A TV may scale a non standard resolution source to display it but with the characteristics that ssddx mentions. When you play the file on a PC with VLC you will notice that the window will change size and shape with the file that is played if not run maximized.