The Dharma Guide: Logo & tunes-skins
There are several skins with advanced features which can be applied to your TV-Library. Your skin may support either TV-Show-Logos or TV-Show-Tunes. A logo should be self explanatory – it is a title- image for the specified show. The Tunes will play as soon as you navigate to one of your show (e.g. If you have a show called 30 Rock and a proper tunes-file in the folder of 30 Rock, the tune will play as soon as you hit the "30 Rock"-entry in the library.
For both of those features most supported skins have built-in support and scripts in order to get the necessary stuff. Search for an option "Run logo script" and/or "Run tunes script" which will then download the necessary files in order to view the advanced features. You may have to apply these features in additional settings of your skin.
Bear in mind that both features generally require some "hacking" on the skin-developers end. If you have any problems with the scripts, please report them to the maker of these scripts. XBMC by default does not have any support for those features built in.