Possible Clues:

• One instalment of the pie's poem
• In incident, help regularly is outstanding, we hear
• Just one bit of cereal, by the sound of it
• 60 minutes of ''CSI''
• Series chapter
• Part of a broadcast serial, say
• Series instalment
• "The Unit" unit
• The incident of the pie throwing does seem funny
• The pie's happening to have been broken over the poetry