The Windows Script File, .wsf, allows one to mark-up in XML different blocks of scripting. One can, in effect, write a script hooking VBScript, JavaScript, and PerlScript together. This looks to be quite powerful for scripters, especially within the domain of systems administration. Often one knows one scripting language better than another, and even more commonly one may exploit the strengths of multiple languages. Imagine combining the ease of Windows operability in VB with the regular expression power of PerlScript with... whatever it is that JavaScript does well. Could be quite a nifty tool.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/script56/html/wsAdvantagesOfWs.asp