How many projects do you work on at once?

I'm usually working on one novel and one shorter piece at any given time.

Or one in revision and one in writing.

Hahaha, I have the same problem. So many ideas, so little time! You just have to be a bit patient. Pick one idea and get to working on it, and if you think that you have the time/mood to work on another, then work on another. Just don't rush yourself.

As for me, I usually only work on one thing at a time, otherwise my mind gets a bit muddled and my ideas and plot direction start converging and I eventually am just writing two versions of the same thing. Not cool.

One at a time for me.
If I get an idea for another one, I will jot it down in my sketch book then ignore it until I finish the draft of my WIP.

uuuuuuuuuuuuuuuuuuuuh, one right now. And if I get stuck on this one, I write a quick short story to wake my muse back up.

One fictional project at a time. I'm always working on something non-fiction, though. Kinda keeps my brain going on another track.

I am only capable of working on piece at a time, no matter what it is.

I admire those who are capable of juggling between different pieces, especially if they vary greatly in scope and tone.

Right now, I'm juggling 4 in different stages of development.

At the moment, actively writing 2, one YA, the other Adult.
Have one on the back-burner, simmering away. I'll start that as soon as I finish the first draft of one of the others.

At any given time: 1-2 novels in galleys, 1-2 novels being written / edited, 1-2 novels being developed, plus I always have at least 1 movie, 1-2 comic books and my comic strips going on. Occasionally I will toss in a short story or a video game. I will also write a non-fiction book or article depending on how things are going. Plus I've been known to blog for people from time to time.

I like to keep busy.

I have one novel in progress with a few shorts for magazines running around in various stages of development.

Just one at the moment, though it is a trilogy and I am about 30% done with the first book so it'll keep me busy for a while. Most of my creative flow is going into this work, so I don't really have any "random thought" for any new projects. I tend to be able to focus pretty well.

I guess I do have a book I started about 15 years ago lying around, but I haven't touched that in more than a dozen years so I am not counting that, though I do plan on rewriting it at some point. Probably next....

Activly working: just one.

But I have an idea for the next book simmering away in my brain. I don't write anything down on it yet, I just let it grow momentum in my mind. I'll notice things that will be good to check out during the research phase, settings worth remembering, etc, but I don't take any notes while working on the WIP.

I reckon that if it's an idea worth remembering, I'll remember it. And my subconscious mind will work on it in a way it would never be allowed to if I wrote things down as I find that the written words tend to trap me. So all though I'm really anxious and eager to get started on the next project, I almost enjoy the fact that I have a WIP to work on first, so that it can fully develop within me before I set out. It's too easy for me to get excited while writing and thus skipping important steps along the way.

Working on one novel and one screenplay/graphic-novel. Working in different mediums makes it doable, but I try to focus on only one prose/fiction project at a time.