I found an example online that used a cursor and didn't protect its own spid from getting killed so I created a different version.

DECLARE @spid INT, @SQL VARCHAR(8000);

SET @spid = @@SPID;

SET @SQL = '';

SELECT @SQL += 'KILL ' + CONVERT(VARCHAR(5), spid) + ';'

FROM [master]..sysprocesses

WHERE [dbid] = db_id('<<YourDatabaseNameHere>>')

and spid != @spid;

EXEC(@SQL);

GO