On the TrueSound website, it offers a free online hearing screening test that you can take in the comforts of your own home. You don’t need to submit any personal information as long as you checkmark the opt-out checkbox at the end of the test. You have to get 70% or better to pass. Best if you use headphones.
Here is a video by ASAPScience that test hearing of different frequencies. As you age, you lose hearing of high frequencies first.
Paper that Sergey Brin and Lawrence Page wrote at Stanford University when they were thinking about the web searching algorithm.
Some more interesting facts about Google on Hongkait including that “Google” started as a spelling mistake. And that the reason the homepage was so bare was that the founders didn’t know HTML very well at the time.