Sometimes I get this itchy, unsettled feeling. I have trouble sleeping, and I find it difficult to focus on any task that requires my full attention (in other words: I suck at my job for a little while). This is a sure-fire sign that I've been neglecting my imagination, and I need to make something, as soon as possible. Playing around with Lego helps, but something more substantial -- a comic or a story -- is much better.
I also sometimes get this feeling when I'm reading. Particular books bring it on. It's happening right now, with Chill  by Elizabeth Bear. Which isn't a big surprise; I got the feeling when I was reading Dust , the previous book in the series, too. This time, though, I've been thinking about what it is specifically that Chill is doing that inspires me to want to make something.
Maybe you haven't read Chill, so here are some other books that did the same thing for me, in the hope that you'll be familiar with one or two of them: The Dervish House  by Ian McDonald, The Scar  by China Mieville, Singularity Sky  by Charles Stross, The Diamond Age  by Neal Stephenson, and METAtropolis  edited by John Scalzi, with stories by Scalzi, Jay Lake, Elizabeth Bear, Karl Schroeder and Tobias Buckell.
I think it might be density of ideas. Reading each of those books (well, I listened to METAtropolis) I felt like I was running to keep up with a huge array of concepts, or characters, and all of their implications and connections and complex interactions. I like that feeling. It's a sort of breathless excitement, like the whole edifice requires my focussed attention, otherwise it will rush ahead without me and I'll stop understanding what's happening. Or maybe it isn't that, maybe it's that those books are so crammed full of ideas that I want to chase after every one of them, even when the narrative is driving me in a particular direction.
There is joy in a tightly focussed story, which explores a small number (one?) of characters, or a situation, or a single idea in depth. But those aren't the stories that make me want to rush out and write. I wonder if this sort of idea-dense writing is a carefully cultivated style for those writers, or if it just seems natural to them to throw so much stuff in? How hard is it to keep everything under control? I remember the first Ian McDonald novel I read, Necroville , just left me confused, and no other book by Charles Stross has excited me quite the same way as Singularity Sky did (although I've liked a number of them a lot).
So have you read any of the books in my little list up there? Can you see connections that I've completely missed? And (this is my favourite question) can you recommend books that you think might give me this feeling again?