NDC plugs presents Fragmental: a fairly complex open source multi-fx plugin for Windows with a combination of buffer and phase vocoder-type effects. The effects routings use a scheme where effects can be moved around with a single mouse gesture, and both modulation routings and amounts can be set together, again with a single gesture.
From NDC site: "Fragmental incorporates a delay, granulator, three phase vocoder effects, a reversinator, and three types of modulation source. Incorporates a very flexible routing scheme capable of serial and parallel effects routings, and a new kind of modulation routing based on a kind of pie chart representation. It should be noted that the presence of the phase vocoder effects mean the plugin has a constant delay of 7680 samples, although PDC-capable hosts (* like for example Cubase) will compensate for this. There are 3 available modulators (red, green, blue) which can each be set to a choice of an LFO, an envelope detector, or a physically-modelled knob."

To download this free full-functional plugin click here. Source code is also available.