Duelling
In many cultures, trial by combat has been fashionable again in the last few centuries.
The church has sanctified this practise for civil disagreements, under the traditional belief that God will give aid to those with a just cause. However, it is still possible that for criminal cases, a person challenged to a duel under local laws could still appeal to the Ecclesiastical Court for a real trial.
In most cases local law applies to duels, although some large organisations, such as guilds, may have their own code for members. Also a group of rich aristocrats known as the Allentria have managed to get their code accepted as the law for any dispute that involves a member of the group, this was achieved by a large amount of political manouvering as well as the obligatory "Financial Gift Packages". For this reason challenging (or giving a reason to be challenged to) a member of the Allentria is generally considered a Very Bad Idea. Link to the Allentria Dueling Code page.