The hours that different people believe fall in this category vary depending on whether one is an early bird or a night owl, but most people would consider any time between 2 AM - 6 AM to be ridiculous o'clock. If you believe midnight is ridiculous o'clock, this is a sign you are getting old. And if you think 8 AM is ridiculous o'clock, you are most likely a college student.
2. John slept until noon because last night he stayed at the bar until last call and got home at ridiculous o'clock.