I just recently realized how many great ideas and projects I've wasted over the years with not riding them to profitability or even releasing them.
Now whenever I come up with something that doesn't leave me alone for a couple of days I just go for it, without any expectations.
The last one I launched was a very simple iOS App (http://airlocationapp.com) which was actually done in less than a weekend, pitched to only a single blog and generated about $700 since launch, which was roughly one month ago.
My best selling apps, a suite of remotes for iOS (http://reemoteapp.com) actually started off as weekend project just like that but initially hit a bigger niche and now turned into my main project/income.
I'm happy to say that I make a solid $2k-$5k with a bunch of niche Apps in the AppStore, see http.//010dev.com
Although this requires a good amount of time, I'm still able to do some freelancing on the side which makes a pretty sweet addition to the above, works out just great.