My favorite recently was the model explained to me where instead of receiving civil services from a single government without a choice, there are multiple corporatist organizations that run business and provide protection/security, a judicial system, enforcers, an executive system, so on and so forth, and you can pick and choose which one you want to be part of, swearing into their system and agreeing to pay your share into their system.

Then it hit me- this form of government already exists, and it is called the Mafia.