For lighthearted silliness:
* As light as a feather: This implies a lack of seriousness and a carefree attitude.
* Like a child at play: This evokes a sense of innocence and simple joy.
* A whimsical dance: This captures the playful, spontaneous nature of silliness.
* A fluffy cloud: This conjures an image of something airy and intangible, not meant to be taken seriously.
For more exaggerated silliness:
* A clown's antics: This highlights the ridiculous and entertaining aspects of being silly.
* A jester's jest: This suggests a playful mockery, perhaps with a touch of wit.
* A runaway train: This implies a lack of control and a headlong rush into the absurd.
* A tangled mess: This captures the chaotic and confusing nature of some silly situations.
For silliness that is borderline inappropriate:
* A monkey in a tuxedo: This suggests someone trying to be sophisticated but failing miserably.
* A broken record: This implies a repetitive and pointless behavior.
* A misplaced comma: This emphasizes the small, seemingly insignificant mistake that makes the whole thing absurd.
Ultimately, the best metaphor for "silly" depends on the specific context and the type of silliness you want to express.