Come join us in the D development effort. We have plenty of productive things to do that will push you past your limits. This kind of work is also good for giving your career a boost - this has happened to many on the D team.
Shhh - need to keep us compiler devs' salaries up!
Just hang out in the forums forum.dlang.org for a while and you'll get sense of what's going.
If you're ambitious, internally motivated, don't need to be micro-managed, and are a crackerjack programmer, you'll be welcome.