Pete Draper has made an 11-part tutorial on creating a tornado using Particle Flow in 3ds Max.
Splice for 3ds Max
Fabric Software has posted a video of the upcoming Splice plug-in for 3ds Max.
Realistic Grass in 3ds Max with V-Ray - Tutorial
Michal Horba from Evermotion explains how to create grass using the V-ray displace modifier in 3ds Max.
Terrain for 3ds Max
You can generate landscapes from real world elevation data with the Terrain plugin for 3ds Max.