How do I convert a timespan, in seconds, to HH:MM:SS?

Often you want to compare two dates and/or times and express the difference in HH:MM:SS. Except there is no decent way to express the relationship this way; the built-in DATEDIFF function returns a single integer (seconds, minutes, hours, days, months, years, etc). 
 
Here is a way in T-SQL to accomplish this: 
 

DECLARE @d1 DATETIME, @d2 DATETIME, @sd INT    SET @d1 = '20050812 05:32:45'  SET @d2 = '20050817 02:15:46'    SET @sd = DATEDIFF(SECOND, @d1, @d2)    SELECT [HH:MM:SS] =       CASE WHEN @sd/3600<10 THEN '0' ELSE '' END      + RTRIM(@sd/3600)      + ':' + RIGHT('0'+RTRIM((@sd % 3600) / 60),2)      + ':' + RIGHT('0'+RTRIM((@sd % 3600) % 60),2)

 
Here it is in VBScript: 
 

<%      Function TimeSpan(dt1, dt2)          If (isDate(dt1) And IsDate(dt2)) = false Then              TimeSpan = "00:00:00"              Exit Function          End If            seconds = Abs(DateDiff("S", dt1, dt2))          minutes = seconds \ 60          hours = minutes \ 60          minutes = minutes mod 60          seconds = seconds mod 60            if len(hours) = 1 then hours = "0" & hours            TimeSpan = hours & ":" & _              RIGHT("00" & minutes, 2) & ":" & _              RIGHT("00" & seconds, 2)      End Function        d1 = "2002-03-27 9:20:25 AM"      d2 = "2002-03-27 9:20:45 AM"        Response.Write TimeSpan(d1, d2)  %>