From TunesWiki

A portable code infrastructure (which counts as its own concrete VM type) which could be said to store a dataflow tree as might be created by a powerful compiler. Source code is available. It's made to work with Oberon, but it's designed to be mostly language-independant, except that the language must have GC, runtime typing capability, and so on.

I'm very impressed; it makes portable code verification and native code generation almost easy.

Update: Juice seems to be a dead project. The Oberon page has noted that support has been discontinued.

[Reviewed by William Tanksley]