Apparently I'm a person who uses a lot of colloquialisms/idioms in my every day speech. Many times I'm asked "what does that mean"? So I've started making a list of things I say that people aren't always familiar with. Here's a starter list and the meanings:
Frumpy - clothing style that usually consists of bagging, careless clothing i.e. sweatpants, large baggy t-shirts, sweatshirts, etc.
Moot point - it generally means "of no practical importance; irrelevant". In one of my favorite Friends episodes Joey explains moot point (or "moo point") as "It's like a cow's opinion. It doesn't matter".
Mrs Grundy - An imaginary character, she personifies the censorship enacted in everyday life by conventional opinion. Basically she's the neighbor who watches through her curtains to see what you're doing and pass judgement on you for it. I first heard of her through Heinlein's books but the character actually dates back to a play by Thomas Morton in 1798.
Sometimes rubbing blue mud in your belly button is an indispensable survival trait - Also from author Robert Heinlein, it's a way of saying that sometimes you do things that don't make any actual sense but you do them anyway because the society you're surrounded with expects you to.
Shiny - When someone asks how I'm doing, instead of saying "good" or "ok" I say "shiny". It's from a T.V. show called Firefly. While watching it I picked it up and it seems to have stuck.
Blueberry picking - Yes, this one is obscure and family related. When an older sister was at a friend's house talking with other classmates the friend's mom suddenly said "blueberry picking!" which had absolutely nothing to do with what they were talking about. Since then when someone starts talking about something completely unrelated to the conversation we say they're blueberry picking.
Once in a blue moon - describes something that happens rarely. A blue moon (by the more recent and popular definition) is the second full moon to occur in a single month. This happens, on average, 41 times a century, or once every 2 1/2 years. An older definition defines it as the third full moon in a season that has 4.
Enough to make a cat laugh - a cat doesn't "smile" so it would have to be pretty funny to make a cat laugh.
Hair past a freckle, eastern elbow time - I can't find the origin of this one but it's a response for "what time is it?" when you're not wearing a watch (or when your kids keep asking every 5 minutes).
A lick and a promise - a superficial effort made without care or enthusiasm. "I didn't have time to clean thoroughly, so I gave the room a lick and a promise."
Some sayings that people get but I just happen to like:
The bee in my bonnet - preoccupied or obsessed with an idea.
It's colder than a well digger's butt - My grandpa used to say this. I've also heard it as "wetter than" instead of "colder than"
Busier than a one legged man in a butt kicking contest
If dumb was dirt he'd cover 'bout an acre
A horse of a different color - currently known to mean that something makes a difference, making it another matter entirely. One guess of origin is a phrase in Twelfth Night (Shakespeare) where it's used as "horse of that color", though in that case it was used to describe a similarity (as in, no matter the color, it's still a horse) rather than a difference as it's now known.
As pleased as Punch - Punch and Judy, puppet characters. My mother has heard of the puppets, it's new to me. I know the phrase but I never knew where it was from. Punch's character is depicted as self-satisfied and pleased with his evil deeds.
A riddle wrapped up in an enigma - a puzzle, difficult to solve. It's a variation on a Winston Churchill quote.
For the first time I actually ROFLOL. This is one of 28 pictures of Do/Don't when raising baby. The Don't images are, of course, obvious but so funny! 
