There is a Maintenance Update available for Revit 2011 x64.
Please use the link below to download the update for 64-bit:
http://updatesdl.autodesk.com/updates/files/rac_x64_ur10.exe
For 32-bit:
http://updatesdl.autodesk.com/updates/files/rac_x86_ur10.exe
The readme file is at:
http://updatesdl.autodesk.com/updates/files/autodesk_revit_architecture_2011_update_1_readme.htm
Enjoy! And remember where you heard it first…