I started one novel, got halfway through, and it stopped cold. There's more story to be told, but it can go one of two ways and I just can't make up my mind which way to send it.
So then I started something completely different and I was making pretty good progress, but two of the minor characters started bugging me for their own book so I started a sequel featuring them. It's actually going better than the previous book because a lot of the groundwork has already been done. However, every once in a while I have to go back to the previous book to work out some plot or setting issue so that I can use it in the sequel. And yes, it can be as confusing as it sounds.
Meanwhile, inspiration for this idea I'd been toying around with for years came to me and I started working on it.
So I guess that means I have four works of progress going right now, although I'm trying to stay focused on WIP 2 and 4.