Hexadecimal Stacking Pseudo-Assembly Language
The Hexadecimal Stacking Pseudo-Assembly Language (HSPAL) is a programming language by User:SuperJedi224 in which a program is represented by a list of six-digit hexidecimal numbers seperated by line breaks (or not at all, the line breaks are optional and, in fact, all other whitespace is forbidden).
Data is stored as 16-bit unsigned integers in up to 256 unbounded-capacity stacks and a single register.
Control structure takes the form of simple conditionals (of exactly one command) and goto statements.
The Hello, World! program:
200021 400000 200064 400000 20006C 400000 200072 400000 20006F 400000 200057 400000 200020 400000 20002C 400000 20006F 400000 20006C 400000 20006C 400000 200065 400000 200048 400000 140000
A (horribly slow) 16-bit Brainf*** interpreter
Translated from Daniel B Cristofani's Brainf*** self-interpreter. It can be found here. Input is program source followed by program input, seperated by an !. Technically non-standard, as it uses unsigned shorts while Brainf*** proper uses unsigned bytes.
The source for a java-based interpreter can be found here.
Additionally, there exists a Ruby interpreter which relaxes the syntactic restrictions mandated by the specification, but otherwise aims to hew very closely to the behavior defined therein.