A term or phrase meaning "to explain in simple words"?

How do you ask someone to explain something in very simple words, understandable by everyone from general public? In Russia we say something, that can be translated like "explain on fingers". What's the correct English for this?

Could you put that in layman's terms?

Explanation.

For clarity, some of the phrases given as answers have more of an "explain it succinctly," than an "explain it simply" connotation. Others have more of a give me the essentials meaning. Here's some more of each (there is some overlap):

Succinct
give me the quick and dirty
give me the Reader's Digest version
what's the TL;DR?

Simple
draw me a picture
spell it out for me
break it down for me
make it plain

Essential
get down to the nitty gritty
get to the meat and potatoes
get down to brass tacks
give me the nuts and bolts
"Just the facts, ma'am"