California's official state dance, West Coast Swing, is a fun social dance that emphasizes improvisation (check out examples of competitive WCS
here,
here, and
here). Originally a form of Lindy Hop, West Coast Swing has evolved into a modern partner dance which can be danced to almost any kind of music and is also degendered (anyone can lead or follow). It's increasingly popular thanks to social media: Learn how to "speak" WCS, and you'll have a community of Westie friends on college campuses and in cities all around the world.
No dance experience necessary. Wear pants and comfortable sneakers/flat shoes.