Blindly implemented binary search (see http://reprog.wordpress.com/2010/04/19/are-you-one-of-the-10-percent/)

BinarySearch.cs

private static bool BinarySearch(int[] sortedHaystack, int needle)
{
    int leftBoundary = 0;
    int rightBoundary = sortedHaystack.Length - 1;

    while (leftBoundary <= rightBoundary)
    {
        int pivotIndex = (int)(((long)leftBoundary + rightBoundary) / 2);
        int pivotValue = sortedHaystack[pivotIndex];

        if (pivotValue == needle)
            return true;

        if (leftBoundary == rightBoundary)
            break;

        if (needle < pivotValue)
            rightBoundary = pivotIndex;
        else
            leftBoundary = pivotIndex + 1;
    }

    return false;
}