You can change your party affiliation to Libertarian as follows:

• Fill in California's web-based voter registration form. This method is only semi-automated. Completing this web form will cause a a paper registration form to be mailed to your mailing address for you to complete and return by mail. 
  --OR--
• Obtain an "old fashioned" paper form yourself from one of these 150 convenient peninsula locations (PDF). This form is pre-addressed and post-paid. 
  --OR--
• Call the County Elections Office at (650) 312-5222 and ask them to mail a voter registration card directly to you. They're very nice and helpful.

The county publishes even more voter registration information on their web site.

Note: When you fill in your voter registration form, copy your name and address from your driver's license to avoid being called for jury duty twice per jury cycle. The jury pool is created by combining voter and driver databases.

Your registration helps keep the Libertarian Party in business. The state recognizes political parties based on the number of registrants in those parties. We need and appreciate your help!