Embperl is a server-side web programming language similar in purpose to ASP. It allows the author of a web page to interweave HTML and Perl such that the web server will interpolate the Perl to produce HTML.
It's most popularly used with the Apache web server and the mod_perl extension. A recent addition to the language is the EmbperlObject facility, allowing pages to be built as collections of objects, complete with inheritence and encapsulation.
Similar setups are AOLserver with embedded Tcl, ePerl, and Microsoft's ASP.