* Formal: "The new policy proved to be ineffectual in curbing the spread of misinformation."
* Informal: "My attempts to get the stubborn cat out of the tree were utterly ineffectual."
* With humor: "Despite my best efforts, my attempt to impress her with my dance moves was completely ineffectual."
* Descriptive: "The hero's efforts to save the day were ineffectual, as the villain's power was too great."
Remember that "ineffectual" means lacking in effectiveness or power, so choose a situation where something doesn't produce the desired result.