If you haven't watched Jonathan Blow and Marc Ten Bosc's Indiecade talk, check it out here: http://www.indiecade.com/index.php/2011/Conference_videos/
They propose mathematics as design inspiration, which is fascinating and produces some mind-bending games. I think another rich source of inspiration is engineering. Engineering is full of problems and - really - puzzles which can be quite fun to solve. I'm a programmer personally, and part of the reason I do it is because I enjoy solving many problems that come up (of course, there are some very unenjoyable problems as well). And I think many of these problems could be neatly and carefully packaged up as games. You need to be careful of course, as many of your players probably have no engineering training, so you need to ease them in and just show them the fun parts.
This isn't anything new, but I thought I'd articulate it. Using programming as a gameplay mechanic has been explored even in board games with RoboRally. So maybe it's worth exploring other engineering activities?
For example, what about focusing on debugging as a gameplay mechanic? A lot of the time debugging is painful, but a certain class of problems can be quite fun to track down. The act of doing the binary search to pinpoint the issue can be quite gratifying and game-like. There's probably a game in there somewhere...
So, to my fellow engineers out there, I encourage you to think about what you do in "work", find the fun in it, and see how you can package that fun into a game.