Receive a really good birthday present this year? Buy your girlfriend some really nice earrings? Don't worry, neither of those gifts are likely to cause you to owe any gift tax (unless, of course, you spend money on jewelry like Kobe Bryant did a few years ago).
Nonetheless, there are some important concepts to be aware of if you ever make a large gift. Gift tax is only assessed on the person who makes the gift, not the person who receives it. Furthermore, you can easily give up to $13,000 each calendar year without triggering any gift tax. (You can give an unlimited amount to your spouse provided your spouse is a U.S. citizen). After that, it starts to get very complicated.
Fortunately, I'm simplified the gift tax rules for you. Take a few minutes to learn all about the basics of gift tax.