Legoland California Resort -this park is about 90 minutes away from Manhattan Beach. It is great fun for younger kids and their Moms and Dads. If you kids like Legos, they will love this park.
Six Flags Magic Mountain has massive monster roller coasters and awesome adventure rides. Their rides are rated as mild, moderate and max! On the max it states "you better warm up your vocal chords because you are going to scream."
In Long Beach at The Pike at Rainbow Harbor there are rides, food and fun. 