Possible Clues:

• Table may be irregular
• Casual affair with boy
• The opposite of periodic table, sort of
• Items required by part-time boards?
• Firm on the up organised a social round noon? It's infrequent
• Irregular altiplano is accommodating bears to the west
• Occurring at intervals
• So conical a shape must be infrequent
• Irregularly occurring
• Odd cola drunk outside foreign casino