Programming/markup languages
Projects grouped by language they are created in. Majority of the projects utilize many languages at the same time.
ActionScript
I've used it only for coding complex animations in Flash.
C
One of the first programming languages that I came in contact with.
C++
Multi-paradigm and one of the most popular programming languages in the world.
CSS
The Cascading Style Sheets are used in presentation layer in web development.
HTML
By far, the most popular language used to display web pages is HyperText Markup Language.
HTML5
Most recent revision of the HTML standard.
Java
Java programming language may also mean Java SE API.
Java Micro Edition
Mobile edition of Java. Current mobile devices either do not support Java at all, or support Java Standard Edition, but it was not the case in the past.
Since great majority of early and even some recent mobile phones supported Java Micro Edition applications (those are called MIDlets), this was the one of the most portable technologies ever created. Nowadays it's very hard to find a technology that spans so diverse set of devices, although there are several technologies that aspire to that status.
JavaScript
Client-side scripting language, very useful in web development.
LaTeX
Document markup language that I use for scientific papers, and various software engineering artifacts such as user guides, business analyses, technical documentations. I also use it to generate certain documents automatically.
PHP
"The" script language of the web. Very widely used, it also powers this website.
Python
Gradually typed, dynamic, object-oriented programming language. Praised for ease of use at small and large scale.
XAML
Markup language used for declarative UI programming in Windows Presentation Foundation.
XML
Markup language that due to its extensibility can be found almost anywhere. I use it often in serialization.