Worst-case scenario: the UEd Goblin wipes the map and burns down your house.

From Unreal Wiki, The Unreal Engine Documentation Site

Novodex is the default physics engine for UnrealEngine3

Content

Links

The Official Website

http://www.novodex.com/downloads.html

There is also Karma and Havok physics.

Discussion

OlympusMons: Didnt really know what to put here so I added the links to the novodex sites.

El Muerte: you know, there are much more physics engines than just the late Karma and Havok.

OlympusMons: Yeah I know I just figured those were more relevant to unreal engine development.