I had a need to do this some time ago. I implemented a well known algorithm from an English standards organization (I've forgotten exactly who).

This is a little shorter than yours and has a pumpkin date associated with it (but it's a long way out).

Here it is:

CREATE function fn_Calc_Easter_Sunday(@iYear int)

returns DateTime

as

begin

Declare @iD int,

@iE int,

@iQ int,

@iMonth int,

@iDay int

Select @iD = 255 - 11 * (@iYear % 19)

If @iD > 50

Select @iD = (@iD-21) % 30 + 21

If @iD > 48

Select @iD = @iD - 1

Select @iE = (@iYear + @iYear/4 + @iD + 1) % 7

Select @iQ = @iD + 7 - @iE;

If @iQ < 32

Begin

Select @iMonth = 3

Select @iDay = @iQ

End

Else

Begin

Select @iMonth = 4

Select @iDay = @iQ - 31

End

RETURN (

SELECT

CONVERT(DATETIME, [Year] + REPLICATE('0', 2-LEN([Month])) + [Month] + REPLICATE('0', 2-LEN([Day])) + [Day])

FROM

(SELECT CAST(@iYear AS VARCHAR(4)) as [Year], CAST(@iMonth AS VARCHAR(2)) AS [Month], CAST(@iDay AS VARCHAR(2)) AS [Day]) a

);

End