How do I get out of a job contract that has no end date?

Restrictive covenants such as this one are looked at with some suspicion by the Courts and are often not enforced, but they sometimes are.  I see no problem with the 120 day notice requirement.  However, if your agreement really says that you can't work at any job within 30 miles of your current one forever, I would be shocked if it was enforced.  If it actually says something like you can't work for any competitor of your employer for a year after you leave its employ, the clause is more likely to be enforced, but still no certainty.  Whether or not the clause is enforceable depends on a large variety of factors, including the type of industry you work in (i.e. 30 miles when you're talking about an air traffic controller is a lot more reasonable than 30 miles when you're talking about a beautician), whether the employee has specialized skills or training, the geographical scope of the provision, the amount of time the provision restricts competition, whether the employee can work in another industry, whether the employer has invested considerable money and time training the employee, whether the employee's work would involve usng his former employer's confidential information, whether the clause prohibits any competition or is a limited restriction (for example, prohibiting solicitation of customers the employee has serviced in the past 6 months), etc.