Khidaka has released KinkyBeep 2.0.3, a sound synthesizer for the Mac designed to build new System alert sounds.
It requires no specialized synthesizer knowledge, using pop-up menus and sliders to create a variety of unusual sounds. These can then be used as alert sounds, sound effects, or edited with other synthesizers.
The new version repairs a few bugs, enables loop play and offers improved copy, paste and export functions. It's a shareware application available for download. Registration costs $10.