Original query:

select daterange(('1990-01-01'::date + (random_between(1,3000) || ' days')::interval)::date,('2000-01-01'::date + (random_between(1,3000) || ' days')::interval)::date) from generate_series(1,1000);

Prettified:

SELECT
  daterange('1990-01-01'::date + random_between(1, 3000) || ' days'::interval::date, '2000-01-01'::date + random_between(1, 3000) || ' days'::interval::date)
FROM
  generate_series(1, 1000)