An evil BASIC interpreter that Microsoft supplied with DOS prior to the 5.0 days. It was a direct descendent of the MBASIC interpreter for Altairs and CP/M machines that got Microsoft started. Its IDE consists of a half-baked line editor and command interpreter. The language requires line numbers and doesn't support labels, making any form of structure virtually impossible and thus creating an almost insurmountable tendency towards spaghetti code and ingraining the coder with terrible habits that take years to rid himself of.

The GW in the name reportedly stands for Gee Whiz.