Antonyms for the phrase "becoming tedious" include "captivating," "engaging," "enthralling," "exciting," "stimulating," and "thrilling." These words are often used to describe activities, events, or experiences that are enjoyable, interesting, and engaging. If something is captivating, it captures our attention and holds it for a long time. When something is exciting, it creates a sense of thrill and anticipation. Meanwhile, a stimulating experience can challenge us intellectually or emotionally. Using these antonyms can help us describe positive experiences and avoid negative connotations associated with boredom and monotony.