“Pssst…your slip is showing.”
"You were flat on “_____________” (whatever song you’re currently rehearsing).
“Can I borrow $5? I left my wallet at home.”
“Mary (insert other choral member’s name) said that color looks horrid on you.”
“Your best friend is sleeping with your wife.”
I’m surprised no one has said this one yet…
“[insert your own fortune here] In Bed!!!”
“Confucius say: man who stand on toilet high on pot.”
“Confucius say: man who fart in chuch sit in own pew.”
“Smart assed skeptic: monkey man will MAKE you believe!”
Yas’m, that’s right. And when you’re messing with the edges right after they come out of the oven, you do have to be verrrrrry careful and pry them up slowly before flipping them. Otherwise you get fortune cookies that look like Swiss cheese. They still taste great, though. 
Hee. You’re evil. I like you very much.
“Please pay your server.”
“Wise man does not eat the yellow snow.”
“Removal of this tag is punishable under city ordnance 1554.8.2b” or “Do not remove tag under penalty of law.”
“Have you tried the Mocha flavored cookie yet?”
“This space for rent or lease.”
“You have been cursed. To avoid curse, slip this fortune into pocket of person on your right, unnoticed.”
Warning: Do not eat fortune!
No user serviceable parts within.
Step 3: Profit! (see other cookies for previous steps)
I love the stock ticker one, by the way.
You will be dead by next Tuesday.
Confucious say “Woman who cooks carrots and peas in same pot very unsanitary”
You will receive a fortune cookie today.
We know where you live.
We found your dog, and he’s VERY close to you right now.
**Learn Chinese – 門+小 – Diu – “Fuck you!”
Your Dinner Companion has been identified as a serial killer. When you get past the ront door, pretend to pick up a coin from the street. Do not get up until the firing stops.
This cookie is # 550. Collect the entire series!
This fortune cookie is sold by content, not by volume. Some settling of the fortuine may have occurred during shipping and handling. You will be
…Fortune. Tape one end of this fortune to the other end, with a half twist in between and you will have a Mobius…
This Fortune Void in Tennessee
By opening this Cookie, you agree to the legal conditions outlined below…
Delete Cookies?
**
In soviet Russia…fortune cookie eats you!
One of my favorite fortunes ever came from the Jack webcomic.
“You will not be able to say ‘in bed’ at the end of this sentence.”
Confucius say, “The way of the superior man is threefold, but I am not equal to it. Virtuous, he is free from anxieties; wise, he is free from perplexities; bold, he is free from fear.” What, you think Confucius funny, you Yankee asshole?!
Some “straightdope-specific” fortune cookie suggestions:
“Ph’nglui mglw’nafh Cthulhu R’lyeh wgah’nagl fhtagn.”
“A 1920s death-ray is trained on you as you read this.”
“This fortune was prepared by Batman.”
“Hi Opal!”
“the ‘Fortune Cookies’ - band name!”
“TubaDiva is watching you.”
“The Mods have moved your fortune to the MPSIMS forum.”
“Sampiro is a magnificent bastard!”
“You are but one of Teeming Millions.”
“I pit you!”
Sadly, none of them are Dopers. To my knowledge. I guess I’ll be able to tell, though, if I give them the fortune cookies, and one of them points and says, “That was you!”
You are going on long trip, cookie impregnated with LSD.
Fu’s pet boarding and restaurant: Let us wok your dog!
Antidote in next cookie.
Congratulations, You are a winner. This is fortune cookie number 1,000,000. Click here for details.
“That’s the way the cookie crumbles…”
I have a fortune-cookie recipe similar (but not identical) to yours, and couldn’t make it work; when I tried to fold the cookies around the fortunes they were always either too-well-done or not done enough. I’ll try again with your recipe; thanks!
But when I was preparing that cookie-baking effort, my friends and I thought up about a hundred fortunes of the sort you’re looking for. I have them all in a table in a Word file, the exact right size and ready to print out. I even matched the sans serif font used for most commercial fortune cookies.
I would be happy to email you the file, if you’re interested.