Thanks to their site being down for maintenance, you can get 30% off at Borders.com until midnight PST tonight, 7/12/10.
The site is supposed to go back up after 8am PST. Just drop in coupon code THANKS712 and start saving on books.
There are a few exclusions on the coupon; mainly anything that is not a book being sold at retail price is not valid.
(Thanks to Mike!)