General antonyms:
* Simplicity: A simple, straightforward event or experience.
* Modesty: A humble, unpretentious event or experience.
* Sparsity: A lack of abundance or grandeur.
* Frugality: A focus on economy and efficiency.
* Restraint: A lack of excess or flamboyance.
* Plainness: A lack of elaborate decoration or showiness.
Antonyms for specific types of extravaganza:
* For a theatrical extravaganza: A small, intimate play or performance.
* For a lavish party: A small, quiet gathering.
* For a grand celebration: A low-key, informal event.
Ultimately, the best antonym depends on the specific meaning of "extravaganza" in your context.