fun, recreational, not serious.
funny, humorous, jesting, frolicsome.
experimental.
liking play, prone to play frequently, such as a child or kitten; rather sportive.
Inspiring serious feelings or thoughts; sombrely impressive.
Characterized by or performed with appropriate or great ceremony or formality.
Of or pertaining to religious ceremonies and rites; (generally) religious in nature; sacred.
Deeply serious and sombre; grave.