At work, we take one week a year, stop normal operations, and focus on personal interest projects. We call it Jam Week and it's intense and awesome! There are a few people that explore individual projects but the vast majority of folks get together to form small teams and work on their own games. These games are later pitched to the company heads and have the potential to become future IPs.
This year, I was on a team of about 10 people, working on a tactical horror game we're call Nullpoint. I was the only concept artist for the week (though a couple other guys had helped get some concepts knocked out before the week began). I started the week by banging out as many props as I could so the 3D guys would have plenty to work on, then I finished the week with a key art illustration that was used for the end flow of our demo. The team did great and we are hopeful that this project will get picked up for full-time development *fingers crossed*
Some of this stuff is pretty rough but, again, (mostly) all knocked out in a week with many development demands besides. Fun!