[hbrouwer]

Here's one a friend and I did in Prolog last year:

https://github.com/danieldk/brainfuck-pl

Why? Because it can be done. And actually prolog's tracing mechanism makes debugging brainfuck code quite insightful.

[bromagosa]

I coded one in Pharo Smalltalk last year: http://www.squeaksource.com/BrainFuck.html It's so slow it's almost hilarious. It took it 8 hours to print an ASCII mandlebrot fractal frame, NO KIDDING.