The most effective fun sites keep core navigation and content accessible while layering in playful details — easter eggs, delightful hover states, unexpected scroll interactions, and personality in copy. Usability forms the foundation; fun is the embellishment.
Rounded shapes, vibrant saturated colours, bouncy spring-based animations, hand-drawn or cartoonish illustrations, playful cursors, informal typography, and interactive elements that respond to user actions all contribute to a fun, approachable feel.