I had not realised this film was by Gilliam, but I grabbed it the moment I saw it was in the video store. Lots of fun, with his take on fairy tales suiting his style perfectly.
The Grimms are played gloriously by Matt Damon and Heath Ledger, cast in the opposite of the roles you would expect (Damon is the gregarious womaniser, Ledger the bookish idealist). This is not any kind of biopic, either. These Grimms are conmen, making up stories of witches to fleece people when they 'save' them from the creatures they invented. However, they end up facing some real fairy tale stuff as the bulk of the story.
The enchanted forest is excellent, with bits and pieces of most of the (real) Grimm's tales sprinkled here and there.
The adventure story is good, fun and fairly exciting. There's plenty of absurdist stuff too, like the over-the-top Italian torturer who ends up allied with the Grimms.
Thoroughly recommended, I'd say this was one of Gilliam's best comic films.
Brothers Grimm (IMBD)
Brothers Grimm (Amazon)