Here's the info. from the Metrolink website:

Metrolink Board Approves New Ticketing Options Starting July 1

Effective July 1, Southern Californians can buy a weekend pass to ride unlimited Metrolink trains for only $10. Unlimited weekend riding will also be added for monthly pass holders at no additional cost. These additions and other modifications to the agency’s fare policy were approved by the Metrolink Board of Directors on Friday, May 13 following a public hearing and broad outreach to passengers for their comments.

The unlimited weekend passes will be valid system-wide between Friday at 7 p.m. and Sunday at midnight and also include connections to bus and rail across the region, except Amtrak, at no additional charge.

“Our new unlimited weekend pass allows passengers to travel across the region at no charge for our monthly pass holders and for only $10 for those who do not have monthly passes,” said Metrolink Board Chairman Richard Katz. “This allows someone to travel to destinations theme parks and civic centers, for one, low fee without worrying about filling up their car with gas or paying to park.”