You need to use this method.

http://trial.autodesk.com/SWDLDDLM/2013/BDSADV/ESD/Autodesk_Building_Design_Suite_Ultimate_2013_English_Win_32-64bit.part01.exe
http://trial.autodesk.com/SWDLDDLM/2013/BDSADV/ESD/Autodesk_Building_Design_Suite_Ultimate_2013_English_Win_32-64bit.part02.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSADV/ESD/Autodesk_Building_Design_Suite_Ultimate_2013_English_Win_32-64bit.part03.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSADV/ESD/Autodesk_Building_Design_Suite_Ultimate_2013_English_Win_32-64bit.part04.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSADV/ESD/Autodesk_Building_Design_Suite_Ultimate_2013_English_Win_32-64bit.part05.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSADV/ESD/Autodesk_Building_Design_Suite_Ultimate_2013_English_Win_32-64bit.part06.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSADV/ESD/Autodesk_Building_Design_Suite_Ultimate_2013_English_Win_32-64bit.part07.rar

You just need to use this method.  The important part is setting your referrer (Referring Page) to http://trial.autodesk.com/

http://trial.autodesk.com/SWDLDDLM/2013/BDSPRM/ESD/Autodesk_Building_Design_Suite_Premium_2013_English_Win_32-64bit.part01.exe
http://trial.autodesk.com/SWDLDDLM/2013/BDSPRM/ESD/Autodesk_Building_Design_Suite_Premium_2013_English_Win_32-64bit.part02.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSPRM/ESD/Autodesk_Building_Design_Suite_Premium_2013_English_Win_32-64bit.part03.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSPRM/ESD/Autodesk_Building_Design_Suite_Premium_2013_English_Win_32-64bit.part04.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSPRM/ESD/Autodesk_Building_Design_Suite_Premium_2013_English_Win_32-64bit.part05.rar
http://trial.autodesk.com/SWDLDDLM/2013/BDSPRM/ESD/Autodesk_Building_Design_Suite_Premium_2013_English_Win_32-64bit.part06.rar

This is about 21 gig in total…

Here is how you can download Revit 2013 using Firefox with Downthemall, and without having to Register or Login or use Akamai:

  1. Install Firefox and Downthemall
  2. Open Firefox, hit ‘Alt’ – Tools – Downthemall Tools – Manager
  3. Hit the Plus sign
  4. Paste the link you want from the list below into the ‘Download’ field
  5. Put http://trial.autodesk.com/ in the ‘Referring page’ field
    (“Referring URL” in other download managers)
  6. Set your download location in ‘Save Files in’
  7. Hit Start!

Links to copy / paste into download manager:

Revit 2013 – combined

http://trial.autodesk.com/SWDLDDLM/2013/RVT/ESD/Autodesk_Revit_2013_English_Win_32-64bit.exe

Revit 2013 – LT
http://trial.autodesk.com/SWDLDDLM/2013/RVTLT/ESD/Autodesk_Revit_LT_2013_English_Win_32-64bit.exe

Revit 2013 – Architecture
http://trial.autodesk.com/SWDLDDLM/2013/REVIT/ESD/Autodesk_Revit_Architecture_2013_English_Win_32-64bit.exe

Revit 2013 – Structure
http://trial.autodesk.com/SWDLDDLM/2013/REVITST/ESD/Autodesk_Revit_Structure_2013_English_Win_32-64bit.exe

Revit 2013 – MEP
http://trial.autodesk.com/SWDLDDLM/2013/RVTMPB/ESD/Autodesk_Revit_MEP_2013_English_Win_32-64bit.exe

NOTE 1 – Autodesk has kinda given approval to using your own download manager before.

NOTE 2 – You could also use Flashget and manually set the referrer



EDIT – Other Autodesk product links (use referrer shown above)

AutoCAD 2013 – vanilla
http://trial.autodesk.com/SWDLDDLM/2013/ACD/ESD/AutoCAD_2013_English_Win_32bit.exe
http://trial.autodesk.com/SWDLDDLM/2013/ACD/ESD/AutoCAD_2013_English_Win_64bit.exe

Update: now try this method

Revit Architecture 2012

Revit Structure 2012

Revit MEP 2012

I recommended using Firefox with Downthemall to download these files. Finally, be sure to confirm the checksums / hashes before beginning the install.
EDIT:  Some people were having problems with these links.  However, this should no longer be a problem.
If you are interested in Student version links, go to this page.