Hey I can contribute here!

You've probably seen these before, but along with malpropisms, I like historical references to our common phraseology:

It was the accepted practice in Babylon 4,000 years ago that for a month after the wedding, the bride's father would supply his son-in-law with all the mead he could drink. Mead is a honey beer, and because their calendar was lunar based, this period was called the "honey month" or what we know today as the "honeymoon".

Before thermometers were invented, brewers would dip a thumb or finger into the mix to find the right temperature for adding yeast. Too cold, and the yeast wouldn't grow. Too hot, and the yeast would die. This thumb in the beer is where we get the phrase "rule of thumb".
I've gotten quite a few email about this one. Here's what seems to be the consensus on the real story: The term "rule of thumb" came from colonial-period USA, there was a law that stated that a man wasn't allowed to beat his wife with anything larger around than his thumb.

In English pubs, ale is ordered by pints and quarts. So, in old England, when customers got unruly, the bartender would yell at them to mind their own pints and quarts and settle down. It's where we get the phrase "mind your P's and Q's".

Beer was the reason the Pilgrims landed at Plymouth Rock. It's clear from the Mayflower's log that the crew didn't want to waste beer looking for a better site. The log goes on to state that the passengers "were hasted ashore and made to drink water that the seamen might have the more beer". Furthermore, some anthropologists speculate that Neolithic people made the switch from wandering and hunting-gathering to farming in order to raise grain to brew beer.

After consuming a bucket or two of vibrant brew they called aul, or ale, the Vikings would head fearlessly into battle often without armor or even shirts. In fact, the term "berserk" means "bare shirt" in Norse, and eventually took on the meaning of their wild battles.

In 1740 Admiral Vernon of the British fleet decided to water down the navy's rum. Needless to say, the sailors weren't too pleased and called Admiral Vernon, Old Grog, after the stiff wool grogram coats he wore. The term "grog" soon began to mean the watered down drink itself. When you were drunk on this grog, you were "groggy", a word still in use today.

Many years ago in England, pub frequenters had a whistle baked into the rim or handle of their ceramic cups. When they needed a refill, they used the whistle to get some service. "Wet your whistle", is the phrase inspired by this practice.