Enter, penetrate, pierce, probe are all words that imply an entry into something. Enter carries the strongest implication of simply going into, while penetrate and pierce are more forceful in nature. The word probe hints at an examination of the inner workings of a thing, as in a person or system.
Entertainment can be at any scale – from a private amusement for two, to dinner and dance for many; to performances intended for an audience of thousands or even more. Entertainment can also be serious, as in the case of a religious festival or ceremony, or a work of satire.