General synonyms:
* Diversion
* Interruption
* Disturbance
* Disruption
* Deception
* Absurdity
* Amusement
* Entertainment
Synonyms emphasizing a mental state:
* Inattention
* Forgetfulness
* Absentmindedness
* Scatterbrainedness
* Confusion
* Preoccupation
Synonyms emphasizing a source of distraction:
* Temptation
* Allurement
* Snare
* Red herring
* Sidetrack
* Detour
More informal synonyms:
* Disturbance
* Bother
* Nuisance
* Trouble
* Pain in the neck
The best synonym to use will depend on the specific situation and the intended meaning.