It's one of my Korean friend's birthdays today so I stalked her FB wall and found some new cute ways to say Happy Birthday in Korean :3
If you're talking to a not super close friend or a coworker its still best to stick with:
생일 축하해요! - Happy birthday
But for really close friends you can joke around with, try out these cute short ways of saying it:
Think of these as Korean version of "happy bday" or "HBD!"