Project Spark - A future Revit LT?

Project Spark is a technology preview of a new future Revit Architecture (BIM) solution. Using Project Spark, building professionals can create designs efficiently with real-world building objects, produce more reliable documentation faster, and share files with consultants using Revit or AutoCAD-based products.

Project Spark looks like a striped down version of Revit and does not support conceptual design, analysis, rendering, advanced collaboration, and API.  It may turn out to be a Revit LT version of sorts.  I would guess they would come out with all flavors of Revit, but they are only testing the architectural version.  MEP and Structural hopefully would be available when released.
Currently, you cannot open Revit Architecture or Revit MEP 2012 in Project Spark. Files created in Revit are not supported in Project Spark. However, Revit 2012 files can be linked into Project Spark.
You also cannot open Project Spark files in Revit Architecture or in Revit MEP 2012.  Because Project Spark uses a newer Revit file format, it is not currently possible to open files created in Project Spark with Revit 2012.

They're looking for feedback on the overall concept, usability, and learnability of the product.

You can download the preview here.


You can view the tutorial here

Revit MEP 2012 Update 2 – September 2011

In case you are too lazy to search to the Autodesk site... I've posted it here

http://images.autodesk.com/adsk/files/Enhancements_List_RME_2012_UR2.pdf

Update 2 is not a full install; rather it is using service pack technology similar to AutoCAD®- based products. Update 1 is built into Update 2, so you don't need to worry about installing the first one before installing the second one.

Improvements made in Update 2 build (20110916_2132):

Autodesk® Revit® MEP 2012 Enhancements

• Improves stability when routing ducts which utilize an elbow or takeoff to complete the run.
• Improves stability when dragging a Panel Schedule into a sheet.
• Corrects the classification of embedded windows within a curtain wall contained within a linked file which is used as the boundary to create spaces.
• Improves the regeneration time of Ducts after applying a Visibility/Graphics Override.
• Improves stability when creating a new zone in the zone editor and specifying an already existing name in the properties palette.
• Improves performance when adding an air terminal to a system.
• Retains System Type when coping elements from one project to another.
• Retains pipe and fitting connections when moving piping layout to another level.
• Improves the display of duct with insulation and lining for hidden line views when contained within a linked file.
• Improves display of insulation on segments when viewed in ceiling plans.
• Maintains the type parameter values for panel schedules viewed on a sheet.
• Maintains circuits when upgrading Revit MEP 2011 projects in Revit MEP 2012.

Autodesk Revit® Platform 2012 Enhancements

• Improves stability when switching the visibility setting of linked file from By Linked View to By Host View.
• Corrects Ambient Shadow on objects which are contained within a mirrored linked file.
• Improves the import of IFC files which contain overlapping walls.
• Improves stability when exporting a project to DXF which contains a dimension style that is referenced more than 255 times within the project.
• Corrects the resolution of the background image when calculating offset and scale.
• Corrects duplicate column creation when using Create columns by Grid when some columns are already created on the grid.
• Improves stability when setting a view to Realistic display mode.
• Improves stability when navigating in 3D view after canceling a Print operation.
• Corrects silhouette display for perspective views in projects with linked files.
• Corrects the angle of Photometric Web based light sources when exported to FBX.
• Retains the original IES files when exporting to FBX.
• Reduces the scenarios where element IDs may become remapped or removed when Synchronizing to Central.
• Improves stability when removing layers from floors, roofs and walls.
• Corrects gbXML export of curtain walls where window openings were classified as air opening when using simple complexity mode.
• Improves stability when accessing HELP
• Help
• Corrects mapping of Cable Tray, Cable Tray Fittings, Conduit and Conduit Fittings when exported to IFC.
• Improves the consistency of beams being unique objects when exported to IFC.
• Improves the placement of slabs when exported to IFC.
• Improves the creation of beams, such as length, when imported from IFC.
• Disables switching to 3D view if current view only is set when exporting to IFC.
• Enables the export of filled regions to IFC.
• Enables mass based curtain panels and mullions to be individual elements when exported to IFC.
• Enables Structural Columns to be exported to IFC.
• Allows elements hidden by category to be ignored when project is exported to IFC.
• Enables Unicode support for both Import and Export of families.
• Changes setting for "Export views on sheets and links as external references" to be enabled when exporting to DGN.
• Allows exporting to DWFx if the view is blank.
• Improves stability when exporting to DWG.
• Improves the export of custom wall hatch patterns to DWG.
• Improves stability after displaying a warning message.
• Enables the use of Family Parameter when using the Material Browser Paint tool.
• Improves stability when modifying part assemblies.
• Improves stability when working within the Phases dialog.
• Improves placement of linked point clouds based upon their origin.
• Improves stability when printing to PDF in batch mode.
• Improves stability when saving a family into the same folder as the type catalog.
• Improves stability when upgrading projects.
• Improves stability when setting a workset from Editable to non-Editable.