You can earn 10,000 Starpoints per referral to the Starwood Preferred Guest Credit Card, up to 55,000 Starpoints per calendar year. That's double the normal Starpoints per referral (but the same annual cap.)

I value 10,000 Starpoints at $250 and 55,000 Starpoints at $1,375.
How does the referral bonus work?
Look for an email with the subject "Limited Time: Refer a Friend, Earn Double the Starpoints" and click the Refer Now button.

The Chase Ink Plus business credit card is offering 60,000 bonus Ultimate Rewards after spending $5,000 in the first three months. During this offer, the annual fee of $95 is NOT waived the first year.

The normal offer is 50,000 points after spending $5,000.