EDIT2 – These links should all be ok now.

Note – copy and paste these links, they are not clickable

These are working:
RAC 2014
http://trial.autodesk.com/SWDLDNET3/2014/REVIT/DLM/Autodesk_Revit_Architecture_2014_English_Win_32-64bit_dlm.sfx.exe
RST 2014
http://trial.autodesk.com/SWDLDNET3/2014/REVITST/DLM/Autodesk_Revit_Structure_2014_English_Win_32-64bit_dlm.sfx.exe
RMEP 2014
http://trial.autodesk.com/SWDLDNET3/2014/RVTMPB/DLM/Autodesk_Revit_MEP_2014_English_Win_32-64bit_dlm.sfx.exe
Revit LT 2014
http://trial.autodesk.com/SWDLDNET3/2014/RVTLT/DLM/Autodesk_Revit_LT_2014_English_Win_32-64bit_dlm.sfx.exe

To download, you could use admintool download as per this link, or just use any download manager.

Revit 2014 download link should be:
http://trial2.autodesk.com/SWDLDNET3/2014/RVT/DLM/Autodesk_Revit_2014_English_Win_32-64bit_dlm.sfx.exe
working now! (not yet live, not working 3.30pm 1 April 2013)

Here is the vanilla AutoCAD 2014 link:
http://trial2.autodesk.com/SWDLDNET3/2014/ACD/DLM/AutoCAD_2014_English_Win_64bit_dlm.sfx.exe

Some things are missing (not live yet), and I guess they will become available soon, like:
http://trial.autodesk.com/SWDLDNET3/2014/BDSPRM/DLM/Autodesk_Building_Design_Suite_Premium_2014_English_Win_32-64bit.sfx.exe

Some notes and other links:
http://trial2.autodesk.com/SWDLDNET3/2014/ACD/WI/{64CFA19F-6192-4CD5-AA9E-77334D584BE2}/SETUP_x86.tar.lzma2
(I don’t know what this is for, it was started during the auto download and install process)

Direct link to the download manager:
https://emsfs.autodesk.com/utility/dlm/prod/Installer/2_000_006/AutodeskDownloadManagerSetup.exe

This will install or upgrade Akamai Netsession.  If you want to learn more about Akamai and Autodesk products, check out this link.

The key folder for Akamai is still C:UsersUSERNAMEAppDataLocalAkamai

C:Program FilesCommon FilesAutodesk SharedAutodesk Download ManagerDLMSession.exe

Link to the downloader / installer:
http://trial2.autodesk.com/SWDLDNET3/2014/ACD/WI/AutoCAD_2014_English_Win_32_64bit_wi_en-us_Setup.exe 

A few things happen when the downloader / install launches, like:
/url “http://trial2.autodesk.com/SWDLDNET3/2014/ACD/WI/AutoCAD_2014_English_Win_32_64bit_wi_en-us_Setup.exe” /akamai /auth authparam /sid SESSION_ID

and
2013/4/1:14:50:48    LJ    LJ-NOTEBOOK    Download    Play    SETUP_CONFIG    http://trial2.autodesk.com/SWDLDNET3/2014/ACD/WI/{64CFA19F-6192-4CD5-AA9E-77334D584BE2}/SETUP_x86.tar.lzma2

You can download Revit 2013 trial version before it is available on the Subscription site for certain Suite users… go figure?

EDIT Go to this link if you want to avoid using Akamai at all and download Revit 2013 directly

If you are having any trouble downloading Revit 2013 trial, follow these steps:

  1. Go to Control Panel, and remove Akamai NetSession Interface
  2. Click on this link, download the installer and run it
  3. In Explorer, browse to: C:UsersYOUR-USERNAMEAppDataLocal
  4. Hold Shift, Right-click on the ‘Akamai‘ folder and click Open Command Window Here
  5. At the command prompt, type:
    admintool clearcache
    Hit ENTER
    (leave the command prompt open)
  6. Start your download from the Trial download link
  7. Keep this command window open, and type admintool at any time to get an update on your download (speed / bytes downloaded).  To do this, type:
    admintool info http://trial.autodesk.com/SWDLDDLM/2013/RVT/ESD/Autodesk_Revit_2013_English_Win_32-64bit.exe
  8. You need to keep the Trial download window open in your internet browser too…

    Interesting comment from the Autodesk deployment blog, Up and Ready:

    We have been getting a lot of posts in our forums regarding corrupt installations and downloads.  My suggestion is to use Firefox and the Browser Download instead of using the Download Manager.

    via
    Downloading Software: Browser Download vs Download Manager – Up and Ready

    I have previously posted about using Firefox and DownThemAll to download Autodesk content.

    There are some other great third party download managers available – which one do you use?

    Jdownloader is quite unique and powerful – check it out if you haven’t before.  From the website:
    It simplifies downloading files from One-Click-Hosters like Rapidshare.com or Megaupload.com – not only for users with a premium account but also for users who don’t pay. It offers downloading in multiple parallel streams, captcha recognition, automated file extraction, and much more. Of course, JDownloader is absolutely free of charge.