While only a qualified doctor can make a diagnosis of bipolar, there are certainly symptoms and behaviors that might make you suspect that you, a loved one or a friend may have this illness.
Having shifting moods, of course, doesn't have to indicate a mental illness. For someone to be excited for days about an upcoming party, then suffer a letdown when it's over, is normal. If that same person exhibits reckless, over-the-top behavior before the party - for example, buying 15 new outfits...
