SmallBASIC
SmallBASIC (not to be confused with Microsoft Small Basic) is a BASIC interpreter, originally intended for use on the Palm line of PDAs, and currently available for POSIX-compliant systems (including Linux, Unix, Mac OSX, and BSD), Windows, DOS, and several lesser-known systems.
SmallBASIC is fairly similar to QBasic, although many keywords are different (for example, DO works significantly different in the two languages).