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 an implementation of BASIC.
Other implementations of BASIC.
SmallBASIC is fairly similar to QBasic, although many keywords are different (for example, DO works significantly different in the two languages).