I have used the scripts below in production (that's why I wrote them, after all), but as always, do so at your own risk. Most should work from Max 9 onwards; there's nothing too exotic here.
download —> CAD Cleaner (0.8 KB): A Max Utility Script to automatically weld vertices and smooth faces of imported and/or converted solid-model geometry. It can take a looong time on complex geometry, so try it on a few simple models first. I think the slowdown is from the weld routine, which can take a while in general.
download —> ChainTread (28 KB): A Max Script to create animated chain treads that follow a spline path. A common usage would be for tank treads or bicycle chains. Enables control of forward, reverse, and mixed (slow, fast) motion via animation of a helper along a path. Ignore the included "readme" file at your own peril! Sample Max file included.
download —> Incremental Transform (1 KB): A Max Utility Script to incrementally transform scale, position, and/or rotation of a set of selected objects. Harder to explain than it is to use.
download —> Mass Image Populate (38 KB): A Max Script to populate selected objects with a series of sequential images. Creates a (2-level) multi-material so you can have the "sides" with a different material than the "front," which would typically have your image sequence. Sample Max (2008) file included. You can see the interface HERE.
download —> Motion Graphics Tools (594 KB): A Max Script with a bunch of commonly used tools for working with motion graphics and standard materials in Max. Match plane sizes to bitmap images, set filtering, self-illumination, etc. Also has a slider/spinner for accessing object visibility, buttons for shadow casting, and more. PDF instructions included. You can see the interface HERE.
download —> Warp Control (3 KB): A Max Script to enable/disable space warp object modifiers, either on all or selected objects. Speed up viewport operations by turning off spacewarps 'till you need them. Includes a "remove" button to remove, as well as disable/enable space warp bindings.