SmallBASIC is a free interpreter for BASIC, a simple computer language, targeting simplicity, mathematics, and graphics. Also, it has a powerfull string library, supports external C modules (shared libs), uses dynamic arrays (by default) and has no data types. Versions exists for Linux (or other Unix), PalmOS, DOS, Win32, VTOS (Helio), and Franklins (eBookman). It uses a lot of drivers, including svgalib, ncurses, and framebuffer.
Ficl (Forth inspired command language) is an ANS Forth interpreter written in C. Unlike traditional Forths, this interpreter is designed to be embedded into other systems as a command/macro/development prototype language. Ficl provides object extensions that can be used to wrap methods and structures of the host system without altering them.