Jay Said:

Is this kind of employment legal in California?

We Answered:

There is no legal requirement to give you benefits or insurance.

However, there is a legal requirement to pay you overtime. Also, if you are being paid hourly, even without overtime you are not being paid minimum wage, which is $8/hour, and more in some cities.

From the Department of Labor, CA:

Any work in excess of eight hours in one workday and any work in excess of 40 hours in one workweek and the first eight hours worked on the seventh day of work in any one workweek shall be at the rate of one and one-half times the regular rate of pay.

You should bring this up to your employer. If they balk, or if they force you to stay with that ridiculous contract, you could contact the US Department of Labor (1-866-487-9243) for advice how to proceed in California.