Here's what searching for the Aussie instrument the "didgeridoo" brought up using FindSounds.com. Or the melodic call of the nocturnal whippoorwill for the bird lovers out there. And who doesn't like punctuating a sentiment with an occasional sad trombone?
Look at the small sample of sound files available online and one could easily find themselves sampling sounds randomly for hours, like meandering from one Wikipedia entry to another.
Think of FindSounds.com as Google Image search, but for hunting down sound effects and audio resources by name, file format, number of channels, file resolution, and sample rate, all in a variety of languages. Not every search time brings back audio clips (phew: "No sounds have been found labelled "Bieber"), but the site proves extremely useful for referencing common sound effects, musical instruments, vehicles, background noise, and animals.