Although it is possible to use include files in ASP
<!--#include file = "path/file"-->
I found that it was not possible to do so during runtime. VBScript seems to be lacking an include function. So I wrote these 3 functions: asp_html_include(), asp_vbs_include(), and vbs_include(). The reason for this is that I could not create a function that executed VBS AND displayed HTML.

<%= asp_html_include(file) %>
will display the html content of file. In order for the function to work without the =, you would have to place a Response.Write(FileContent) at the end of the function.
asp_vbs_include(file) will execute the VBScript code inside file. Note that file must only contain VBS, no ASP tags or HTML. vbs_include() is just like asp_vbs_include() but made for command line VBScript files, it also happens to be the fuction that I derived the other two from.