[US Users Only] 2-for-1 freebie: Get a free 48-hour Xbox Live code when signing up for Bing Rewards to earn a 1-Month Xbox Live Gold Trial from search
XboxTrial gives away Xbox Live codes for completing an offer. They currently have an offer to simply sign up for Bing Rewards with email or Facebook account, and they'll give you a credit for doing so redeemable for a 48-hour code. You can also use Bing Rewards to sign up to search with Bing, and earn a 1-month Xbox Live membership for doing as little as 100 searches.
Note: You must be in US for link to work properly.
UPDATE; This promo is now over, but you can still sign up for Bing Rewards