Here are some synonyms for "banal":
* Trivial
* Hackneyed
* Clichéd
* Ordinary
* Mundane
* Stale
* Insipid
Here are some examples of how "banal" might be used:
* "The movie's plot was so banal, it was hard to stay awake."
* "Her speech was full of banal platitudes."
* "He was tired of hearing the same banal jokes."
The opposite of "banal" would be:
* Original
* Exciting
* Unique
* Provocative
* Thought-provoking
* Remarkable