Not sure if this is the right forum or not… But here goes.
My kids have asked me to make up a joke involving a policeman, a robber and possibly a key and handcuffs.
I know A LOT of jokes, but not many are approriate for young kids. So… I turn to you, the great minds of SDMB.
Remember, young kids. Let’s have em.
A policeman and a robber walk into a bar. The officer is carrying handcuffs. The “key” is, is that there brothers.
Retarted I know, but hey, you asked for it.
Kinda makes you wonder whos “Retarted”!
Well there goes the vodoo dick joke.
So far, all I can think up is this:
A policeman is walking down the street late one night. He notices that the door of the seafood store has been forced open, so he walks inside and turns the lights on.
He sees a man trying to escape with an octupus.
“You’re under arrest!”, yells the policeman.
“For what?”, asks the man.
“Armed robbery.”
Why did the somewhat slow police officer order new handcuffs that had an extra cuff?
Because he heard a report that 3 armed robbers just held up the local bank. 
These are great! I’ll be sure to share them with my kids. They’ll get a big kick out of these.
No offense, CRorex, but I think I’ll have to pass on that one, though.
Mike was walking down the street with a computer under one arm, a photocopier under the other and a desk strapped to his back. A policeman stopped him, placed his handcuffs on the guy and said ‘I’m placing you under arrest.’ ‘Why?’ asked Mike. ‘For impersonating an office sir.’
A motorist was unknowingly caught in an automated speed trap that measured his speed using radar and photographed his car. He later received in the mail a ticket for $40 and a photo of his car. Instead of payment, he sent the police department a photograph of $40. Several days later, he received a letter from the police that contained another picture… of handcuffs.
A policeman saw two little boys making the family dog pull their billycart around so he called them over.
‘You can’t make your dog pull the billycart’ he said ‘It’s cruelty to animals’.
The policeman then noticed a piece of string tied around the dog’s testicles, the other end was firmly held by one of the lads.
‘You can’t tie string to your dog’s testicles’ the policeman said ‘That’s even worse!!’
One boy turned to the other ‘What are testicles?’ he whispered.
‘Dunno’ his friend replied ‘He must be talking about the overtaking gear!’.
Not all have a robber and handcuufs, but they’re close…
ok, I’ll retool a Fireman joke to fit your criteria…
A policeman is fucking a robber in the ass in a holding cell. The chief walks in and says “Hey, what are you doing to that prisoner?”, the officer replies “Sir, this man was going into cardiac arrest”, the chief says “Well, then give him CPR for crissakes”. The officer says “I did, how do you think this shit got started?”
ummmm…on second thought, don’t share that one with the kiddies.