对别人说生日祝福除了说“Happy Birthday”还能说什么？

There are already some great answers. So I just want to add some funny ones.

Here are some things you can say:

Standard

• Enjoy your special day!

• Have an awesome/great/fabulous/wonderful/spectacular/amazing birthday!

Funny

• You're not 30; you're 18 with 12 years of experience!
  

• Congratulations on surviving another year!
  

• Congragulations on another year of skillful death evasion!

• Happy “Welcome to the World Screaming and Naked' Day! (Use this only for someone you are really close to.)

  
  

I hope this is helpful.