Singapore Airlines is having a pretty straightforward bonus to get new KrisFlyer members. Sign-up as a new member to their frequent flier program and get 500 KrisFlyer miles!
Make sure you enter promo code JOINKF2017, and signup by April 14, 2017.
I don’t fly SQ often, but I have, and it’s obviously a great product. If you think you’ll be flying them in the future, doesn’t hurt to sign-up and get a few free miles, though 500 miles won’t get much.