This should be a seriously FUN part of the whole Box Lunch Lifestyle experience! But we get that spending time doing what we want just because we're inspired to can lose its place in our busy lives. We're out of practice. But we also hear people say, "But I don't have anything I want to make or build or explore...I'm pretty much fine. I don't do 'those things.'"
We're not buying it.
If your fifteen minutes of time at lunch doesn't yell, "I'm starting a website!" or "I'm learning origami!" (and yes, some people DO want to learn origami...), this is a chance to listen to some quiet dream that's been hiding. Just sit for fifteen minutes with a blank piece of paper. Play some music , or find a nice view to enjoy if you can, but just sit, and think, and remember. We know it sounds "yogi-y" but you might be surprised what bubbles up in your head. For example, you might remember a class you loved in school but never really "got" because you didn't have [enough time, the right teacher, etc.]. Why not "get it" now?
Make a note or two. See what tomorrow brings. And give yourself credit for making space for that hidden, quiet dream to speak. This kind of listening is tough, but you're tough enough.