Punctual is a language for live coding audio and visuals. It allows you to build and change networks of signal processors (oscillators, filters, etc) on the fly.

Wasmer enables super lightweight containers based on WebAssembly that can run anywhere: from Desktop to the Cloud and IoT devices, and also embedded in any programming language.

in:verse is a programming language and environment for exploring the conflux of poetry, visuals, mathematics and code.

Faust (Functional Audio Stream) is a functional programming language for sound synthesis and audio processing with a strong focus on the design of synthesizers, musical instruments, audio effects, etc. Faust targets high-performance signal processing applications and audio plug-ins for a variety of platforms and standards.

Pre is a PHP preprocessor, designed to make adding new syntax effortless. It's also a collection of pre-built macros, which we use because they make our code clearer and simpler.

modernish is an ambitious, as-yet experimental, cross-platform POSIX shell feature detection and language extension library. It aims to extend the shell language with extensive feature testing and language enhancements, using the power of aliases and functions to extend the shell language using the shell language itself.

TLA stands for the Temporal Logic of Actions, but it has become a shorthand for referring to the TLA+ specification language and the PlusCal algorithm language, together with their associated tools.
TLA+ is based on the idea that the best way to describe things formally is with simple mathematics, and that a specification language should contain as little as possible beyond what is needed to write simple mathematics precisely. TLA+ is especially well suited for writing high-level specifications of concurrent and distributed systems.

Elixir is a dynamic, functional language designed for building scalable and maintainable applications.

Elixir leverages the Erlang VM, known for running low-latency, distributed and fault-tolerant systems, while also being successfully used in web development and the embedded software domain.

paste and execute code online.

TidalCycles (or Tidal for short) is a language for live coding patterns.
It allows you to make musical patterns with text, describing sequences and ways of transforming and combining them, exploring complex interactions between simple parts.

Crystal is a programming language with the following goals:

Have a syntax similar to Ruby (but compatibility with it is not a goal)
Statically type-checked but without having to specify the type of variables or method arguments.
Be able to call C code by writing bindings to it in Crystal.
Have compile-time evaluation and generation of code, to avoid boilerplate code.
Compile to efficient native code.

Hack is a programming language for HHVM. Hack reconciles the fast development cycle of a dynamically typed language with the discipline provided by static typing, while adding many features commonly found in other modern programming languages.
Hack provides instantaneous type checking by incrementally checking your files as you edit them. It typically runs in less than 200 milliseconds, making it easy to integrate into your development workflow without introducing a noticeable delay.
It is backward compatible with PHP and provides tool to convert from one to the other.

Zephir, an open source, high-level/domain specific language designed to ease the creation and maintainability of extensions for PHP with a focus on type and memory safety.

Despite its popularity, few know that JavaScript is a very nice dynamic object-oriented general-purpose programming language. How can this be a secret? Why is this language so misunderstood?

Cappuccino is a framework which makes it easy to create advanced web apps. With just a few lines of code you can have an app built with full undo and redo, truly amazing table views, drag and drop and every modern UI appearance and behaviour you might expect on the desktop.

A C-Based Audio Programming Language

SuperCollider is an environment and programming language for real time audio synthesis and algorithmic composition. It provides an interpreted object-oriented language which functions as a network client to a state of the art, realtime sound synthesis server.

Pure Data (aka Pd) is an open source visual programming language. Pd enables musicians, visual artists, performers, researchers, and developers to create software graphically, without writing lines of code. Pd is used to process and generate sound, video, 2D/3D graphics, and interface sensors, input devices, and MIDI. Pd can easily work over local and remote networks to integrate wearable technology, motor systems, lighting rigs, and other equipment. Pd is suitable for learning basic multimedia processing and visual programming methods as well as for realizing complex systems for large-scale projects.