Query for total downtime of site using datestamps and status columns
Would this work.  I just had the query give the totals for each year.  You could easily filter by date if you wanted to restrict it for just this year, or a specific year you are looking at.

Also, this assumes the final record in the table is an up time.  If you end with the site being down, then that last downtime isn't included.  You should get your site back up before worrying about calculating downtime :).

WITH TAB
AS
(
    SELECT * ,
           Row_Number() OVER (Partition BY Site ORDER BY DateTime) AS RowNum
    FROM @Table
)
SELECT UT.Site , DATEPART(Year, UT.DateTime) as Year,
       Sum(DateDiff(second, DT.DateTime, UT.DateTime)) as TotalDownTimeSeconds
FROM       Tab AS DT
INNER JOIN Tab AS UT
    ON DT.SiteStatus = 'Down'
    AND UT.RowNum = DT.RowNum + 1
    AND UT.Site = DT.Site
WHERE DT.Site = 'ZooToys'
GROUP BY UT.Site, DATEPART(Year, UT.DateTime);


If you want to get the down time for the past 60 days, add to the where clause: 

UT.DateTime &gt; DateAdd(day, -60, getdate())