Courtesy of FW, we have this Discover More promo:

Get a $100 CashBack bonus when you’re approved by April 6, 2008 and make $500 in purchases with your card within 3 months.

In addition, there is a balance transfer offer of 3.9% until January 2010, but it carries a balance transfer fee of 3% with a min of $10 and no cap. To apply, visit apply.discovercard.com and use promotion code: DAFM.