PS. I thought I'd check the spelling of 'gueule' - how could I fail to after the spiky post below - and I found this fascinatingly complete (as in, containing strictly irrelevant but nonetheless fascinating information) definition, on Everything2:
In the most literal sense, amuse gueule translates from the French as an amusement for the mouth - but not a mouth in the human sense - amuse bouche would be used in that case (which indeed it sometimes is). It seems that gueule means a non-human mouth, either that of an animal or more intriguingly, a gun. When used in reference to humans, gueule is a slang term, roughly translating as gob. It gives you an idea of the playfulness of the dish.