Large Object Manager
Allows you to set objects over a certain number of faces to appear as a box. Aids navigation in polygon-heavy scenes.
Standard Maxsripts (.ms) can be run from the Maxscript button in the utilities panel. To have them always available - save the scripts into your scripts/startup directory.
Macroscripts (.mcr) can be placed in either scripts/startup or UI/Macroscripts - and are then accessed through the 'Customise User Interface' menu in 3dsmax. You can then assign the script to a keystroke - or a button. All macroscripts will appear under the 'Dusk' category in the dropdown.