Which scripting language?

I'm writing a game. It will have a full level editor, so it needs an embedded scripting language for custom events.

Guile, Lua, or Python?

>>1
Before jumping on the LUA bandwagon, have you considered Squirrel?
http://squirrel-lang.org/
It's a really nice, embeddable scripting language, which is quite painless to bind, imperative style (supporting OO) and has a really small footprint (90kb for static lib)