Possible Clues:

• Lacking originality, as a joke
• Drink — after second time, urinate
• There's nothing new about the story that comes at the end of this
• The way beer gets past its best
• Like days-old bread
• Stagnant
• Like unfunny jokes
• Like an old cigar
• Like many a crossword clue for the word OREO, or like old Oreos
• Monsters