I got this idea at a conference and it works wonders and makes journal reading really fun!
As a beginning sentence you give only the beginning of a proverb such as:
"People who live in glass houses shouldn't....."
The students copy the beginning sentence and finish it with whatever they think suits it. With my grade 3 class there was almost always someone who came up with the real ending without knowing it.
We also got things like:
"People who live in glass houses shouldn't...
Walk around naked."
" A penny saved is.....not much."
"A bird in the hand is worth....more than money because that would only happen once in a lifetime."
The tricky part is coming up with the proverbs for the kids, I think I got my list on the internet somewhere.