Well, it's definitely that time of year; that time of year when the egg nog starts to get hinky. Always a dangerous time. I'm one, of the roughly four people in existence, that drinks egg nog on a semi-regular basis. I'd drink it all year long, but they only make it in November and December. After that, you take your chances.
So I'm taking them. And there's really only one way to tell if the egg nog in your refrigerator is still 'good.' What you do is you take an 8 oz (ounce) glass, you fill it to the very brim with egg nog and then you slam it down in as few gulps as possible. Then you take a few steps back. And quietly observe.
Some further tips: If the egg nog tumbles out of the container in thickish clumps, the game is over, my friend -- and you've lost. Do not pass go. Just grab a chair and wait for November to roll around again. Sigh wistfully if it helps.
Oh, and this is really important: if you begin to vomit as though your life depends on it, don't fight it. Your life might truly depend on it. Just let it all come out. Wipe that dirty slate clean. If you have hair, you might want to ask someone you know to hold it back for you (so that it doesn't become intermingled with your vomit).
Finally, take this post with a grain of salt. And remember, the boneyard is littered with the skeletal remains of folks who have taken my advice. God rest their once merry souls..