A short 3-day cruise is a great getaway. These quick cruises are available from LA and Long Beach all year. They are affordable and lots of fun.
3-night cruises from Los Angeles go to Ensenada, Mexic0. Ensenada is at the northern end of the Baja Peninsula, a short trip from California. Activities include shopping for silver and pottery, kayaking, horseback rides, and sunning on the beach.
You may also want to look into 4-day cruises from Los Angeles.
For more options, see the 3-day cruises from California.