ReBasic VM and core libraries.
It can run in a console mode, but mostly usable within a browser shell.
Check out rebasic.mix for the web shell project and documentation.
ReBasic can run most of the examples from old BASIC books. The difference is only in I/O operations, drawing and all the PEEK and POKE magic you can find in the VIC20/C64 dialects.
Can be install locally by running ./install script.