RolloSONIC is a fully-freeware, fully-modular sound-synthesis environment, with mouse-guided tweaking and real-time module interconnection. Like the great module racks historically used in making sound effects for science-fiction movies, RolloSONIC lets you add and connect a bunch of audio-processing modules together, where the sound is playing the entire time so that changes to the interconnections and changes to the sliders are heard immediately -- just like with the real thing. RolloSONIC takes the idea to the next level by letting you incorporate your mouse movement into the control channels. Optionally, you can also incorporate your USB or MIDI (musical) keyboard controller and its knobs and sliders into the mix of control data. Making experimentation easier, RolloSONIC is freeware, can (optionally) run without installation, and it has been designed from scratch, with no third-party frameworks, making it much more efficient on system resources than most other audio-generating software.