I've been a MODO beta tester for five years, focusing on modeling and UVing workflows that are game-engine friendly. Below are a few macros I've written to streamline my asset production.
This macro breaks a selected face into triangles by beveling inwards and join-averaging the resulting vertices. This also works on selected adjacent faces. It was authored to work on quad faces, n-gons, and primitive caps for geometry intended for game engine use (where everything has to be triangles or quads). Base MODO has a command called Spikey that does something similar, but requires an additional mouse click.
This macro cuts a face selection and pastes it into a new Mesh Item.
Recommended key mapping: Shift-N
This macro tears off selected polygons from a mesh and gives the user move handles similar to the Tear Off functionality in the UV Transform command.
Recommended key mapping: Shift-P
Select at least one subdivision surface face before running this macro. The macro will select all connected faces and convert them from subdivision surface to polygonal geometry, also removing all interstitial edges between the original subdivision surface edges. This macro is useful for quickly converting high-resolution subdivision surface geometry to low-poly game engine-friendly mesh. Because the macro is running a Freeze operation, you get a result that respects the SubD mesh more closely (taking edge weighting into account, for example).