The MOD DUO is an open source based effect pedal which can be loaded with all sorts of different effect models, all free and open source.
For those of you who don’t know what open source is, it is a software movement which aims at sharing the source code so that you can augment it or change it yourself which in turns benefits the community.
I can’t comment on the quality of the models first hand but this is quite an interesting product.
Anyway, this video probably explains this a lot better, it illustrates a Kickstarter project, which means you can get your hand on one by supporting it:
This post is also available in: French