Possible Clues:

• Greek who plays Number Three for Oresteia
• Saucy line he's put into play?
• Writer of 17-, 19- and 34-Across
• Playwright to halt poetic panther
• 'Prometheus Bound' playwright
• Old stager turned out such easy learner
• Prometheus was bound to inspire his writing
• Marathon participant won at least thirteen literary prizes
• Classical Greek playwright
• Playwright can generate extremes of hilarity in funny clauses