Adding a fast random row to a table in postgresql

ALTER TABLE posts ADD myrand DOUBLE PRECISION;UPDATE posts SET myrand = RANDOM(); CREATE INDEX myrand_posts ON posts(myrand,id); ANALYZE VERBOSE posts;
ALTER TABLE posts ALTER myrand
SET DEFAULT RANDOM();
ALTER TABLE posts ALTER myrand
SET NOT NULL;
--SELECT * FROM posts WHERE myrand >= (SELECT RANDOM() OFFSET 0) ORDER BY myrand ASC LIMIT 1;

Boolean column in a table in postgres

CREATE INDEX polls_active_idx ON polls(done) WHERE done='t';

how to get auto align css centering ala mybloglog and facebook

body { width:99%;max-width:1024px; margin:auto;text-align:center; }
#wrap { margin: auto; width:85%; text-align:left; }
#main { float:left; width:74%; margin-top:1%; }
#sidebar { float:right;max-width: 25%;width:25%;min-width: 5%; padding:3px; }
#footer { background:#cc9; clear:both; }