Looking at light helps me sneeze when I feel I'm just about to sneeze but for some reason won't. In most cases the light triggers the sneeze, and I'm not left with the sensation of an un-sneezed sneeze.

I started doing this when I read about it somewhere, and I got the impression it's universal. I haven't experienced lights causing unwarranted sneezing though, but perhaps it's the same thing, only some are more sensitive than others.