I heard this one on Unsolved Mysteries years ago, and it’s always stuck with me: “the light at the end of the rainbow.”
Can I tell on my girlfriend? She’d gotten into the amusing habit of deliberately mangling “casting aspersions” as “casting asparagus” and then one day in a moment of distraction said she didn’t want to be guilty of “throwing asparagus”.
From an old English paper that I read and helped a friend edit:
“A virgin forest is a forest in which the hand of man has never set foot.”
In a newspaper article 6 or 7 years ago a CIA (FBI?) official was complaining that some mistake they’d made or been perceived to make hadn’t really been that bad, wasn’t the point, was not important
“This red herring’s been hanging around our necks too long”
Boxer Vinnie Paz on ESPN’s “Friday Night Fights” once used the phrase “He’s not the sharpest marble in the drawer.”
Well, I guess that’s the whole thing in a bombshell.
This thing came at me like a fish outta hell.
This metaphor mixing is a walk in the cake.
I’m so tired, I could eat a horse.
From the Rachel Maddow show (Air America Radio): “We poke a sharp stick at the soft white underbelly of the right-wing scheme machine.”
Mmm… soft white machine underbelly…
or…“You can lead a horiticulture, but you can’t make her (him) think.”
Groan (I love it).
Few more for the toilet paper roll:
“I want to make sure we’re all on the same plate.”
“Some people sail through life on a bed of roses like a knife slicing through butter.”
“I’m shooting from the seat of my pants.”
To tweak a couple of noses, I’ll say, “It’s not rocket surgery or brain science.”
oops, I forgot to properly attribute that (paraphrased) to Dorothy Parker.
“I made it by the skin off my neck”
My wife once told me that I had been “snoring like a light”. 
I love her more than anything, but sometimes she’s not the sharpest bulb in the drawer…
If you need to hang on to something in order to cover your ass, you want it “preserved for posterior”.
That is a whole new can of fish.
Not the brightest bulb in the greenhouse.
Let’s cut some new water.
That was easy as falling off a piece of cake.
That is similar to the time I told my co workers that, " I might go to Keeneland on Saturday if I get a crazy rabbit."
They just stared at me, I knew something wasn’t quite right.
“If I get a nutty bunny?”
Nope, they just look confused. Then one of them has an idea.
"OMG I think she means “wild hare.”
They then had to explain to me it was wild hair, short for wild hair up your ass.
I had no idea. And my co workers tell me the phrase “crazy rabbit” instead of “wild hair” lives on, long after I have stopped working there.
I’ll burn that bridge when I cross it.