GWBasic
Nobody really knows what GW stands for, some say "Gee Whiz". The oldest version of Microsoft Basic, was part of MS-DOS up to and including version 4.0, afterwards it was replaced by QBasic. In IBM-PC DOS it was simply called basic, and accompanied by BASICA, a somehow advanced version that would run only on IBM machines.
Blast Off is a tutorial.
KindlyRat's GWBasic Page with some old GWBasic games.
Exil is a bytecode-language that (when it's finished) can execute GW-Basic programs, after converting them to an own format.
Bumderland Games has two GWBasic games.
Some more GWBasic games on the PowerBASIC website. PowerBASIC is an - expensive - compiler.
There are quite a lot of Turkish GWBasic sites, I notice.
QBasic
It replaced GWBasic with MS-DOS version 5.0, 1991. It now had quite a comfortable editor, and no need for line numbers any more.
QBasic Games
Beginner's Programming Tutorial in QBasic
The BASIC Archives
Jeremy's QBasic Homepage
O.H.R.RPG.C.E. is a game creation system written in QBasic.
Chipmunk Basic
is a freeware old-fashioned Basic Interpreter, accelerated for the PowerMac, yet still compatible with old 68k Macs running System 6. There is a Windows version too.
Try this site: http://social.microsoft.com/Forums/en-US/genuinefeedback/thread/7de9e1c5-0688-4724-beca-c228c7f2e38c