Probably several ways of doing that, but this one will work:

WITH a (aval, astamp) AS (

SELECT min(value), min(t_stamp) from @t

WHERE value = (SELECT min(value) FROM @t)

)

, b (bval, bstamp) AS (

SELECT min(value), min(t_stamp) from @t

WHERE value = (SELECT max(value) FROM @t)

)

SELECT

a.aval

,a.astamp

,b.bval

,b.bstamp

FROM

a

CROSS JOIN b

John