Possible Clues:

• Shut up with a loony
• Georgia repeatedly out to lunch
• Slang for crazy - apply a gag
• Silence adult, senile
• Enthusiastic, to say the least
• Senile and retiring? That's a joke!
• Joke by one in senile dotage
• Grand commander becomes senile
• Cracked a joke first
• Go __ (rave)