Possible Clues:

• Performed solo (of a comedy routine)
• Finish the sitting
• The thin one and a fat one falling over in a sort of comedy
• Acknowledge the national anthem, say
• Kind of comedian to fail to keep a date?
• An applauding audience will, disconnectedly, for a really good one?
• Laurel awarded finally excited comedian
• Fail to keep an appointment or date
• Open mike night format, perhaps
• Comedian on his feet