So betwixt my last work environment and my current one, I had begun going down the path of (again) building my own software. I had (have) a number of ideas - but that's really the easy part. And I'd say "good ideas", but, in my humble opinion, the difference between a "good idea" and a "bad idea" is in the execution.
Which is to say, its value you accrue in arrears, not a judgement you can really make a priori.
I suppose - best case - you hope its a good idea before you start doing it.
In any case, I had 3 things I did actual work on to a real degree (in terms of execution): some middleware, a web app-y thing, and a tool. They had some overlapping technology components but with reasonably distinct market segment targets. Given where I am now, I'm thinking I'll release them each in some form over the next few months - no sense letting them rot on my harddrive.
So - check back; more info soon.