A lot of teams (especially design teams) want to build their own projects (maybe it's a fun experiment, or a full-blown product). This is the only technique I've see work to actually ship something aside from your regular consulting work.
Every once in a while our product team will isolate a larger project and do exactly this. We always get out of our co-working space, and we go heads down on a major feature or part of our product.
We talk about it for sometimes weeks ahead of time and get really excited and pumped up about it, and it's always a lot of fun.
We always make sure to introduce a new workflow or some new technologies (our last week of hustle was the first time any of us used AngularJS) as a way to use this as a learning experience too.
I highly recommend this for any product team.
Sweet! Can I add this quote to the post?