I thought I would start a thread where we post and attempt to solve brain teasers.

Anyway here goes...

The prisoner

A man is being kept prisoner on an island. All around the island is freezing water which you can't swim in and boats to and from the island are banned. The only way to get to and from the island is on a footbridge.

The footbridge takes 10 minutes to cross.

However, every five minutes a guard looks out across the bridge to see who is crossing it. You need the correct documents to cross the bridge either way. If the guard sees you crossing the bridge he demands to see the documents or he sends you back.

The prisoner escapes, how does he do it?

Post yours

He shows him the correct documents...

I win :D

Wrong, remember he is the prisoner, he doesn't have the correct documents.

Oh OK...I thought I was being clever :)....Lemme think about this one...

EDIT: Can you walk across the frozen water??

He kills the guard?

It does seem to be a largely guard dependent security measure.

Nope, the water is not frozen, just cold

Every 4 minutes, the prisoner takes a few minutes to hang under the bridge thus preventing the guard from seeing him. They do it in movies under trucks all the time

he runs

He tells the guard he is visiting the prison, and is sent "back" to the mainland...

OK, I am reaching...

Nope, he is a prisoner and he is a guard, he would just tazer the hell out of him.