This is it, you're on cloud 9. Hollywood is going to make a film adaptation of one of your favourite franchises or novels. Your head is spinning. Hell, you even know who the perfect actor is to play the lead role.

But as quickly as your excitement soars, it comes crashing down when you find out they've cast Matthew McConaughey.

Welcome to my nightmare. Welcome to some of the worst casting decisions ever made.

Feel free to share your own. Not a member? Sign up here, it's free.

5. Matthew McConaughey as Thomas Sullivan Magnum, IV (Magnum P.I.)

It seems only fitting to start with the Hollywood brain-fart that inspired this blog.

Now, the final call has yet to made on this as McConaughey has only been offered the part. But if you make plans to kill someone, you can at least be charged with conspiracy to commit murder.

Therefore, Hollywood is guilty of conspiracy to ruin a perfectly good franchise by casting a horrible actor in the lead role.

I mean, he clearly doesn't have the mustache to back it up and special effects have yet to reach the level where they can make one for him.

          ....
                                The mustache that started it all vs. peach fuzz

Not to mention that "Magnum P.I." isn't a romantic comedy co-starring Kate Hudson.

Who should play the role

Tom Selleck is still around and his 'stache is as powerful as ever.

                                  ..
                                        Still puts younger 'staches to shame

If you think he's too old (shame on you), mixed-martial-artist Don (The Predator) Frye is perfect. He's 20-years younger and is the spitting-image of Selleck.

                                  ..
                                       Deadly in the mustache martial arts

4. Keanu Reeves as Don John (Much Ado About Nothing)

If there's one thing theneilman respects, it's guts as a filmmaker. No matter what other people say, you stay the course and make sure your movie turns out the way you want it.

That being the case, it goes without saying that Kenneth Branagh is bravest director in film history. Why? Because he agreed to make a Shakespearean film starring Keanu Reeves.

                                  ..
                                                Hark! There is no spoon-ith

Who should have played the role

Pop over to the IMDb. Any actor on this site would have been a better choice.

3. Dennis Hopper as King Koopa (Super Mario Bros.)

If you think Hollywood butchers classic novels, just take a look at what they've done to video games over the years.

With the exception of a few odd success stories (Mortal Kombat, Street Fighter), all video game movies have been utter crap. But the worst of all has to be Super Mario Bros. It takes a perfectly established franchise and mangles it so badly that it ceases to have anything in common with the games.

There are just so many things wrong with this film (why does the Mushroom Kingdom look like Brooklyn?). I mean, take a look at their casting for the main villain.

                                  ..
                             Bowser -- King of the Koopas and Mario's nemesis

Portrayed by:

                   ..
                                               A spiky-haired Dennis Hopper

Now I know what you're thinking. How can Hopper play Bowser? He looks nothing like a dinosaur. And you would be right. Give yourself a treat.

But fear not, the filmmakers have an air-tight explanation for everything. You see, according to the film, Bowser evolved from a dinosaur into Dennis Hopper.

And they actually paid someone to write this crap!

Who should have played the role

Honestly, CGI or animatronics would have been the way to go. But this film was doomed from the start.

2. Arnold Schwarzenegger as Mr. Freeze (Batman and Robin)

I'm a huge fan of Arnie. Total Recall and Predator both played big roles in making me the person I am today. But even I can't justify him being cast as Mr. Freeze.

          ....
                            All that make-up work and he still doesn't look the part.

Though he has been portrayed a few different ways, Mr. Freeze is actually a sympathetic character. While trying to find a cure for his dying wife, a freak accident freezes him to the bone.

It's really hard to feel sorry for a gargantuan Austrian who spouts out bad lines constantly and can single-handedly bring down an Boeing 747.

Who should have played the role

Patrick Stewart would have been perfect, but even he couldn't save this horrendous film.

                                  ..
                                        Mr. Freeze's warm-blooded twin

1. John Wayne as Genghis Khan (The Conqueror)

Man, to be a fly on the wall when it was decided that The Duke would play a Mongolian emperor in a historical epic.

There's really not much that needs to be said here. After all, a picture is worth 1,000 words.

                                  ..
                            Well, Pilgrim, I see you're still protecting the ladies.

Who should have played the role

No idea. But, uh, not John Wayne.