DECLARE @d1 VARCHAR(20)
DECLARE @d2 NVARCHAR(20)
DECLARE @d3 VARCHAR(20)
DECLARE @d4 NVARCHAR(20)
DECLARE @d5 VARCHAR(20)
SET @d1 = '2004-06-23'
SET @d2 = '2004-06-23'
SET @d3 = '06/14/2011'
SET @d4 = '06/14/2011'
SET @d5 = 'May 20 2011'
SET @d1 = DATEADD(YY,1,@d1)
SET @d2 = DATEADD(YY,1,@d2)
SET @d3 = DATEADD(YY,1,@d3)
SET @d4 = DATEADD(YY,1,@d4)
SELECT convert(VARCHAR(20),CAST(@d1 AS DATETIME),101) AS 'Cast of d1'
SELECT convert(VARCHAR(20),CAST(@d2 AS DATETIME),101) AS 'Cast of d2'
SELECT convert(VARCHAR(20),CAST(@d3 AS DATETIME),101) AS 'Cast of d3'
SELECT convert(VARCHAR(20),CAST(@d4 AS DATETIME),101) AS 'Cast of d4'
Results:
Cast of d1
--------------------
06/23/2005
Cast of d2
--------------------
06/23/2005
Cast of d3
--------------------
06/14/2012
Cast of d4
--------------------
06/14/2012

DECLARE @B BIGINT
SET @B = 922337
SELECT convert(VARCHAR(20),CAST(@B AS DATETIME),101) 

DECLARE @B BIGINT
SET @B = 2958457   
WHILE @B < =  2958464      
   BEGIN
      SELECT convert(VARCHAR(20),CAST(@B AS DATETIME),101),@B
      SET @B = @B + 1
   END

SELECT convert(VARCHAR(20),CAST(@B AS DATETIME),101) WHERE @B < 2958463

DECLARE @B BIGINT
SET @B = 41046   
      SELECT @B AS 'Bigint',CAST(@B AS BINARY(8)) AS 'Binary 8',convert(VARCHAR(20)
      ,CAST(@B AS DATETIME),101) AS 'Date'
SELECT CAST(GETDATE() AS BIGINT) AS 'Bigint'
,CAST(GETDATE() AS BINARY(8)) AS 'Binary 8',GETDATE() AS 'Date'
Result:

Bigint               Binary 8           Date
41046                0x000000000000A056 05/19/2012
41046                0x0000A0560090F582 2012-05-19 08:47:46.780