They will go on a scavenger hunt where they will find items for their lunch (Clues I've added below)

We are making a huge ark out of butcher paper and hanging it on the wall with a rainbow over the top. Once the kids have gathered their food from the scavenger hunt, they will gather into the "ark" area.
We found music with rain sounds in the background so the kids will feel like they are in the ark and it's began to rain.

This is the scavenger hunt we came up with. You may have to change it to fit your needs.

It's time to gather
Some food for you
Like God commanded
Noah to do.

You must leave at once
There's no time to gain
Look for the clues
Before it starts to rain.

(These top 2 sayings will be in an envelope for each group to start out with along with one of the clues below as the first clue)
The clues below we gave to each group, but they were in a different order for each group so that each group wasn't going to the same place each time)

Go to a place
Where the food is kept cold
No need to think twice
Just do as your told. (frig in the kitchen--sandwich)

The rain is coming
Time is growing late
Go gather some food
It's in room # 8. (bag of chips)

Now go out the north doors
Don't stop for a rest
Turn right and go 10 long steps
Where you'll find an ice chest. (juice box)

Now go back inside
And take a long walk
To a place during Primary
Where you stand to give a talk. (cookie near the primary podium in the primary room)

Because you have been obedient
And followed each clue
You'll be blessed like Noah
For being faithful and true.

Now go back to the ark
It's time to eat
Go find a table
And take a seat