1. The first recorded April Fool's Day prank in California occurred in 1863, when a San Francisco newspaper reported that the government was planning to sell The Presidio, a military fortification. The story caused a panic among citizens, and the newspaper was forced to publish a retraction the following day.

2. California Governor Ronald Reagan declared April 1st as "Ronald Reagan Day" in 1969, in honor of his 58th birthday.

3. In 1979, the California State Assembly passed a bill that proposed changing the name of the city of San Francisco to "San Francisco-Beijing" as a symbol of unity with the People's Republic of China. The bill was an April Fool's Day prank, but it gained widespread attention and caused controversy.

4. On April 1, 2001, the Disneyland theme park in Anaheim, California introduced its newest attraction, "The Junkyard Jamboree". The ride features a collection of musical instruments made from junk, and has since become a popular attraction at the park.

5. In 2018, an April Fool's Day prank by the Los Angeles Police Department caused public backlash. The department tweeted that it had arrested "Freeway Rick", a former drug kingpin, for drug trafficking. The tweet was later revealed to be a joke, but many criticized the department for making light of a serious issue.