Getting a taste of your own medicine
Being treated how you have been treating others
Let the cat out of the bag
share information that was a secret
Like two peas in a pod
Two people who are always together
Once in a blue moon
rarely happens
At the drop of a hat
do something instantly without hesitation
Sleeping like a log
Sleeping very soundly
Biting off more than you can chew
Taking on a task that is too much to handle
Pulling someone's leg
joking with them
The ball is in your court
It is up to you to make the next decision/step
Run like the wind
to run very fast
He has bigger fish to fry
He has more important things to take care
Raining cats and dogs
Raining very hard
You can't judge a book by its cover
Can not judge something based on its appearance
HItting the nail on the head
Performing a task with precision
When pigs fly
Something that is impossible
Fit as a fiddle
Being in good health
It cost an arm and a leg
It is very expensive
Piece of cake
a task/job that is easy to complete
Take with a grain of salt
Don't take it too seriously
Feel a bit under the weather
feeling slightly sick
Busy as a bee
To be very active and working hard at something
Best thing since sliced bread
a good idea, invention or plan
Don't count your chickens before they hatch
Don't count on something happening until after its already happened
A dime a dozen
Something that is very common, not unique