BlitzMax - BlitzMax is a game programming language from Blitz Research that is based on the BASIC programming language. - http://blitzbasic.com/Products/blitzmax.php
Omikron Basic - an efficient and powerful programming language for sophisticated software development. Ideal for scientific and engineering purposes. - http://www.berkhan.com/basic/start_e.htm
METAL BASIC - METAL is a free modern extended BASIC metacompiler for PowerMac used in scientific research, development and K-12 education. - http://www.iit.edu/~sarimar/GDS/
TNT Basic - TNT Basic's amazingly easy to use development environment allows you to compose all your game's graphics, sounds, music and code with simplicity and ease. - http://www.tntbasic.com
VIP BASIC - Visual Interactive Programming for BASIC. It can create 68k or PPC applications. Good for extensive database programming, but it builds excessively large applications and is slow at most things. May not be good for creating many kinds of games. - http://www.mstay.com/legacy.html
Chipmunk BASIC - An old-fashion BASIC interperter for the Macintosh. - http://www.nicholson.com/rhn/basic/