(1) PHP
PHP stands for pre hypertext processor, and it is one of the most common languages out there, and is often used for websites. It is open source and therefore has spread very quickly and is what powers a large number of massive websites out there on the web: look at things like facebook pages and most massive online social networks and database driven sites and you will find out that they use PHP to serve their pages.
(2) ASP
This is a microsoft product and is sometimes contrasted with PHP, in the sense that people tend to use either one or the other for the dynamic server side elements of their websites.
(3) Perl
A popular language often used to create and run small scripts. Back in the day CGI scripts used to be all the rage for instance for things like website contact forms and similar and these were served by Perl. It is still quite popular with many people and makes opening and reading from files and various other simple tasks very straightforward indeed.
(4) C#
This is C sharp rather than C-hash, and is a popular type of language in the C family. Skills in this language or C++ are highly sought after, and a large number of programs are now written in this. Those who are currently at university studying programming are quite likely to learn something like C# and possibly something like Java too.
(5) Java
Java is a popular language and has been around for many years. It is often used on websites in the form of something called an applet, if you see a coffee cup logo and wait a few seconds or more for some interactive element of a website you visit to load, then that is something in Java loading. A popular language and often learnt at university, Java programming skills are quite useful and desirable, although probably not quite as much as C# or another C type of language.