Language Details: Lua

Lua is a powerful, fast, lightweight, embeddable scripting language, combining simple procedural syntax with powerful data description constructs based on associative arrays and extensible semantics.

Official website (see also: Wikipedia article)
Code Jam 2010 Contestants using Lua
Qualification Round
Used in 18 solutions by 9 contestants:
Round 1B
Used in 8 solutions by 2 contestants:
Round 2
Used in 4 solutions by 1 contestants:
Round 3
Used in 1 solutions by 1 contestants:

Submission Origin

United States (3 contestants)
Brazil (1 contestant)
Denmark (1 contestant)
France (1 contestant)
Mexico (1 contestant)
Poland (1 contestant)
Slovakia (1 contestant)