Last autumn I've started a small web-site with collection of programming problems for beginners. To solve the tasks here users are to submit answers calculated after processing some randomized data. I.e. it is resembling ProjectEuler which I admire greatly :)
http://codeabbey.com/ - that is how it looks like.
Now I want to add a new functionality - mini-challenges to write the smallest code possible - i.e. there would be some tasks for which the length of solution is assessed and ranked.
However, while all other tasks could be solved in any possible language (and users even are not required to post their sources, though they usually do this) since it is not clever to compare the length of solutions in different languages.
Instead I want to choose some minimalistic language, probably esoteric - and build the interpreter into my site, so the solution is processed to check it validity. All users will use only such language for such "minification" tasks and it would be easy to compare solutions.
The only problem is that I'm not sure what language would be suitable. Brainf--c and Whitespace are too esoteric - they have different programming model at all. Befunge seems closer, but it is two dimensional :D
I had an idea to use my own "language" - for example this:
however I'm not sure it is quite suitable - initially it was created for quest game engine (which I failed to complete).
I would prefer some better known language, especially with a number of usable tools...
So here am I looking for help / suggestions. You see, I do not know much of esoteric languages and it seems now I really need a good advice. So thank you in advance! :)