I thought this would be fun to share with all the Dopers here.
Every day I decorate my daughter’s lunch bag with an original and different message or decoration of some sort…
…And I’m keeping a blog about it here:
http://weirdlunchbag.blogspot.com/
My daughter absolutely LOVES that I do this. Every morning she doesn’t know what will end up on her lunch bag. It’s a total surprise. Her friends also look forward to it as well.
Love these! Thanks for posting. How old’s your daughter? Mine was a junior in HS this year, and I wrote her notes (most very brief) in her daily lunch. Might have to switch her to brown-bag-it so I can emulate your example. 
My mother used to put notes in my lunch bag. One of them said, “Help! I’m being held prisoner in a school lunch factory.”
My daughter is 13 and will be entering 8th grade next year. My intent is to do a different one every day she goes to school until she graduates… or asks me to stop. 
I’ve experimented with putting a few notes inside her lunch bag in addition to decorating the bag itself.
That’s awesome. It’s great that her friends like them too.
My mother used to put notes inside my sandwich. I ate at least half of them.
muldoonthief is right; it is awesome. Little stuff like this is what they remember for the rest of their lives.
My daughter sometimes makes my lunch and puts little notes in it. I have them posted on my cube wall. Everyone else at work is jealous.
Regards,
Shodan
Good on you!
My daughter is the exact same age and I do the same thing- when she takes a throwaway lunch (for field trips, etc.). I usually do a picture mixing up two unrelated things: tyrannosaur with wings, an orca with a unicorn horn, the Sorting Hat putting Anakin in the Sith House, a Xmas tree and an orca falling on Magretheia (sp?). If I write anything it is something like “Keep Cold: Donor Organ Transplant” or notes to her friends that “E’s dad packed her a bad lunch, so keep an eye on your own as she may try to grab things when you aren’t looking”. She hated it in elementary school, but loves them now. Go figure!
I can in no way draw well which adds to the charm/amusement of her friends- one of her friends’ mothers commented about it so I made one for her as well. It is hard to come up with good ideas- I may go your route of deciphering/decoding messages.
Here’s an idea. Figure out a way to carefully unglue (steam, perhaps) the bag so you can open it up and draw/write something on what is the inside surface, then glue it back together. You may need to use something that won’t bleed through the paper and ruin the surprise.
Sadly the nice story first reminded me of the beginning of I Smile Back.
My mom did this for us. I was just talking about it this weekend, and it’s been thirty years since she did it.
That is a great idea! We are getting down to the last few days of school where she will be bringing in her lunch, so I will probably try that out at the beginning of the next school year.
Also, if anyone has any other creative ideas about this, please feel free to suggest them here.
What kind of stuff did she put on your lunch bags?
I haven’t done much artwork on her lunch bags. I’m like you. I am not an artist, (though I can draw Snoopy pretty well as today’s lunch bag demonstrates) but I like the idea of drawing a mixture of two unrelated things. I will have to try that and see how it goes.
Slightly thread-jack here, but this same concept works for grown-ups too. I used to have a VW Vanagon Westfalia (a VW camper van) and everyone who owns one of these buys parts from 2-3 specialty parts dealers, all based out of California. 99% of their business is conducted through UPS or USPS.
One of these vendors (Van Cafe) became a little bit famous for being over the top customer focused. So much so that when one guy ordered parts, in the section of the online order form that said “Special Requests” he wrote " I would like the box to have a fire breathing dragon on it" as a lark. When his order showed up, someone had drawn an exquisitely detailed purple dragon with red flames on the USPS Priority Mail box. A real piece of art, right up there with any graphic novel artwork.
This led to multiple people requesting their box be decorated, and their wishes were almost always granted.
They earned so much good will in our community from this small act. Even adults like people drawing for them!
I always used to draw a cartoon on little duck’s lunch bag. I have a cartoon cat based on an old friend that went with her to school every day.
We had a saying VERY similar when I was in high school!! 
If you are driving through the desert
in a canoe, and all of a sudden,
one of your wheels falls off…
How many pancakes does it
take to cover a doghouse?
A creative idea - pick something she likes and look up weird facts about it.
300 Random animal facts
The weirdest law in every state in the union.
Top 10 Darwin awards winners. (Hey, kids are morbid, too!)
A group of (____) is called a (_____.)
A glaring of cats, a murder of crows, a pandemonium of parrots, a busyness of ferrets. (Bonus points if you can make it rhyme!! 
)
Great minds think alike, Mind child, and those are some great ideas. I will be sure to include them when she starts back in the fall.
You could get food safe markers and draw directly on her sandwich for a surprise
Inspired by Disheavel’s suggestion, I present today’s lunch bag.
It’s a dragon riding a unicycle.