If you're forgetful by nature, I'm sure you've goofed an introduction before, or forgotten someone's name after meeting them a few times. If this sounds familiar, you're in luck because Emily Post has some suggestions for the next time you're in a predicament like that!
Don't panic. Embarrassing as it may be to stumble over a name, don't fail to attempt an introduction. If the person is attentive, he may see your hesitation and cover for you by introducing himself. If the person is wearing a name tag, you might take a quick peek. Otherwise, you should apologize quickly and say that you've suddenly forgotten the person's name. Do the same if you aren't sure of someone's last name. ("I'm sorry Aileen, but I don't know your last name.") The person should fill in the blank for you. There's no need to continue apologizing for your lapse.
I like her advice, but in the heat of the moment, you might not be that quick on your feet so tell me, how do you save face when you've forgotten someone's name?