Have you tried journaling? It lets you get ideas out (adding or remixing ideas from the previous days), without investing in getting a project up, writing code, etc. A lot of times, for me, I just want to explore an idea and I'm not actually interested in working through it. But if I spend enough days journaling an idea and I'm still interested in it, then I go for it.
The other thing that's helped me is realizing that anything worthwhile is hard. If you want to stick with a project until it's done, you're going to get bored, you're going to run into roadblocks, and you want to cultivate a sense of "this is what I want to do, and that is just a temporary issue that I will work through".
Last thing that's helped me is finding a support group. I use irc, specifically I hang out on irc.darwin.network (shameless plug, I kinda co-run it), there I can chat with people about what I'm working on, they can ask cool questions, etc, keeps the juices flowing and reminds me why a project is worth sticking to.
Re your first paragraph: What's funny is that I get almost the same effect by avoiding writing ideas down. I find letting an idea sit and stew in my head to be a good vetting process.
If I forget an idea, that's a feature of the system, not a bug. If an idea survives for a while and I find myself coming back to it often, then after a month of it being an idea I might act on it. At that point the idea is a lot less nebulous and I have a pretty clear idea of where to get started and an idea of where it's going to go in the future.
The other thing that's helped me is realizing that anything worthwhile is hard. If you want to stick with a project until it's done, you're going to get bored, you're going to run into roadblocks, and you want to cultivate a sense of "this is what I want to do, and that is just a temporary issue that I will work through".
Last thing that's helped me is finding a support group. I use irc, specifically I hang out on irc.darwin.network (shameless plug, I kinda co-run it), there I can chat with people about what I'm working on, they can ask cool questions, etc, keeps the juices flowing and reminds me why a project is worth sticking to.