(will return random 50% of rows)
   select *
   from table
   where sin(rand (datepart( ms  , getDate())) * [rowIdenity]) > 0

(or to randomly sort)
   select *
   from table
   order by sin(rand (datepart( ms  , getDate())) * [rowIdenity])

(or select random 25%)
   select top 25 percent *
   from table
   order by sin(rand (datepart( ms  , getDate())) * [rowIdenity])



select random numbers from 10-100 in steps of 10
	cast (sin(rand (datepart( ms  , getDate())) * [rowIdenity]) * 10.1 as int) * 10