Related Clues:

• Comic's one-liner
• Crack up
• Yuk it up
• Be playful
• Cackle or chuckle
• It may start with someone entering a bar
• One may begin "Knock knock"
• React to a 19 Across
• Farce
• Be in stitches
• Amused reaction
• Express mirth
• Bust a gut
• One often takes place in a bar
• 'What a ___!'