Possible Clues:

• 'The lowest form of humor,' per Samuel Johnson
• "My bike won't go because it's two tired," e.g.
• One of about 3,000 in Shakespeare's plays
• Play on a name, say
• Quip
• What's oddly missed in quip taken the wrong way?
• Groan-producing wordplay
• ''Frank and Ernest'' or ''Hi and Lois''
• "Whirled peas" is one
• "When the smog clears in California, UCLA," e.g.