LunaticPython allows genuine two way communication between Lua and Python; in particular, you can load Python modules.
Here is a good tutorial on using Lua for Perl programmers.
LuaPerl also allows the calling of Perl code from Lua. As the author says "I have so much Perl code lying around (and there is so much more in the CPAN archives) that it would be a crime to leave this huge potential untapped."