If you have signed up for credit card sign-up promotions in which you need to spend a certain amount in a few months to qualify for the bonus, American Express gift cards can be useful. The problem with these gift cards is that there is usually a purchase fee. However, you can waive these purchase fees with promo codes. This My Money Blog post
has a list of several of these promo codes. Most have expiration dates of either 6/30/12 or 8/15/12.