I don´t really know how this came to my mind, but here it is. Thor and Loki talking in rhymes. :D Enjoy it. and let me know what you think about this.
(Just to make it clear - bold text is Thor, the italics is Loki)

Loki wandered across his cell, hands joint on his loins, head bowed and paid no attention to his surroundings. This was quite an unfortunate event, but nothing what couldn´t be managed by few minutes of thinking. He was calm, there was no need to hurry and make some hasty decision.

And yet he wasn´t given the precious time he needed. He heard some noise and at first he tried to to pretend he didn´t notice it, but at last he couldn´t ignore the familiar steps, he couldn´t ignore the coming person who he knew was his brother. His heart started to beat faster, but he was able to hide it. Like he usually did.

Hey, brother, how are you?

I have already felt worse.

But you´re a bit lonely, aren´t you?

What do you say? I don´t see the sense.

Loki stopped and gazed at his brother who was stepping on one place, nervously. Loki´s lips formed into an amused smile.

I came to offer my help.

I don´t want it, not that you can.

Why don´t you believe me?

I don´t believe any man.

I´m your brother.

No, you´re not.

We´ve got the same father.

No, we don´t.

They didn´t notice they came closer, their noses were just few inches far and yet so distant. Loki clutched his hands into fists and the hammer in Thor´s hand began to sparkle. They both feared the latter will feel how nervous they were, but both the gods were too busy staying calm to pay enough attention to the other.

I can get you out of there.

That would be generous, I must say.

Can´t you be serious for a while?

Did you forget? I´m vile.

Loki grinned at his brother, showing him the smirk he got used to wear when he wanted to hide his true feelings.

Why do you resist?

Why don´t you understand?

You can return to us.

Don´t start about this again!

I won´t give up so easily.

Then you´ll be disappointed.

You´re member of my family.

Don´t be so naive about it.

Thor frowned when he realised Loki wasn´t joking. He really meant it. He was denying all the good days they shared, all what they experienced. Loki was denying him. It was more hurtful than Thor thought it might have been.

Why are you so angry?

Don´t ask when you know.

Why do you abandon me?

It´s not you, it´s my fault.

Then become who you used to be!

You´re like a little child.

Why? Because I believe?

No. Because you´re blind.

Why do you say I´m blind?

You believe world can be good after all.

Trust me, I can restore your mind.

You can´t take back what´s gone.

Loki bowed head, not daring to look into Thor´s piercing eyes. He knew he was just trying to help, but he couldn´t let him do it. He wouldn´t admit it, it cost him a lot of effort to say it to himself, but he cared about Thor much more than he wanted to. And therefore he couldn´t let him do something as stupid as trying to save him. However it was difficult to not obey him.

Look, I know I was childish.

What a sentiment!

And that I was selfish.

What an astonisment!

Don´t make fun of me!

I have to, you act funny.

And what should I do?

Nothing, just don´t be a fool.

Their eyes were shining and for a little while Thor believed they might burn a hole into the glass wall between them and he could hide Loki in his arms like he had used to do when they had been younger and comfort him, tell him everything was going to be alright.

Well, if that´s what you want…

Please, don´t pretend you care.

I´ll leave and never come back.

You act as if it´s my nightmare.

It was painful for both of them – for Loki to say it and for Thor to hear it. Loki knew it had to happen and Thor was confused. He expected many things from Loki, begging, threatening maybe even truth and sincerity. But not this – not rejection or even denial.

Loki, who´s done this to you?

Everybody and nobody, I don´t care.

If there´s anything I could do…

No, I´m cursed; I don´t belong anywhere.

Loki turned away from Thor, needing time to fight the tears. Thor really cared about him, really wanted to help him and yet he had to act he doesn´t care about that.

So we shall say goodbye.

Don´t be pathetic.

If you´d want to come back home…

I wouldn´t be welcome.

You´ll always be my brother.

And you´ll no longer mine.

We should stay together.

You know we can´t.

Loki´s hand was searching for Thor´s, at least behind the glass, but he realised what he wanted to do and quickly hid arms as far from Thor as possible. It hurt him, hearing Thor offering him they should stay together – what he had wanted his whole life – and not being able to accept that.

I know, but I don´t agree.

Life is not fair.

Despite it should be.

That´s not our business.

Loki´s voice was sharp and unfriendly, unlike his eyes which were shining with tears of loneliness. Thor was trying to see what the emerald eyes of his brother were telling him, but he wasn´t successful – as usual, they were too deep, too complicated just like Loki was. Thor was never able to understand him, he was far too intelligent.

So this is my farewell.

I hope you won´t regret it.

Guard yourself well.

Don´t be afraid, I got it.

And remember I´m here.

As if I could fogret you.

Good bye then, dear.

I´ll remember you.

Loki couldn´t swallow all sobs but fortunately for him he was too silent for Thor to notice. He felt he should say something more but it took him a bit more time.

Let whoever you believe in

Lead you through everything.

Let whoever you believe in,

Bless you, my little brother.

Thor´s eyes gazed at Loki, willing to hear those words from him – that he changed his mind and is going with him. He didn´t know why he cared about his brother so much after he attacked Earth – his beloved Earth – but right now he realised how much he missed Loki. He might not be his own brother, but they grew up together, he was Thor´s first friend. He couldn´t really deny him. And now, when he was about to face need to kill his brother, he felt he couldn´t do it. He had to offer Loki some help.

Thank you, Thor.

I hope you won´t repeat

My faults and won´t have to feel

My despair and guilt.

Thor wanted to reply, to say something, but Loki turned away from him. The god of thunder spent few more moments staring at his brother´s back but he didn´t seem to be willing to turn around, so at last Thor walked away, leaving Loki in his doubts and misery alone.

He knelt down, face hidden in hands and tried to stay calm, but it wasn´t possible. His thoroughly build mask of unconcern or even derision has torn into pieces and went away when he was alone. He couldn´t his loneliness any longer. It was so painful he felt he might kill himself if he was able to. Right now, he could only kneel there, cry and pity himself, regret everything he had or hadn´t done, lack all those sweet moments he and Thor shared. He felt so miserable, so desperate and so guilty when he realised it was his fault they were separated. But he had had no idea how to draw Thor´s attention. Yes, he had been taking him out with his friends, but Loki couldn´t have helped the feeling he hadn´t been wanted. He hadn´t mind the others hadn´t like him, but Thor´s discomfort about him had hurt him. So he had tried to change, to become more interesting so his brother would notice him. Apparently he had, but it wasn´t what Loki wanted.

Tears started to flow down his cheeks, he was shaking with sobs and the whole world disappeared from his sight. Nothing was important but his sorrow and misery. He didn´t care somebody was probably watching him – he just hoped it wasn´t Thor. Because he could no longer keep his feelings for himself, so he started to whisper to himself.

I only wanted to make you

Like me, appreciate me, be proud of me.

Because, in my point of view,

You´re perfect, that´s what I see.

I was just very lonely,

I begged for your attention.

I know I behaved dreadfully,

But it was my desperation.

You were right about me,

I´m mad and should be guarded,

I only wanted to make you feel,

As desperate as I did.

I´m not flawless

And I realise that.

It was senseless,

I regret what I said.

I don´t know if you can

Forgive me, but please,

If you ever cared about me, then,

Let your fury decease.

I beg for your forgiveness,

I´m all yours, I´ll do anything,

Because now I feel emptiness,

I don´t lie, without you, I´m nothing.

So at last I´ll say.

I hope one beautiful day,

I will be able to reach you.

I love you.