Given that many job applicants apparently can't write a Fizz-Buzz implementation, I'd say that being able to implement an algorithm is probably a reasonable way to cull the herd by a hefty margin.
Print numbers from 1 to 100, except print Fizz for numbers evenly divisible by 3, print Buzz for numbers evenly divisible by 5, and print FizzBuzz for numbers divisible by both 3 and 5.