I missed a day. My apologies. If it is in consolation to my loyal readers, I was working very hard that day and I am still in pain. I'll post a second one for today to get things even. Update: It looks like I posted two in one day.
By 'Idea' I mean something practical. This might be an improvement or something new but it should be practical. For example: "We should all have jet packs." While a great idea, it's not very practical. If I had an idea on how to improve the thrust/weight ratio, then that would be a practical idea. That being the only real problem that would need to be solved for jet packs.