I read about this yesterday, and dreamed about it last night. Vividly. So I'm gonna try to go out and see it, if only to see dream imagery appear in real life.
Two moons of Jupiter (Europa and Ganymede) are going to be simultaneously casting shadows on Jupiter Thursday and Friday. A pretty rare event. Jupiter clears the horizon about 8 p.m. or thereabouts, so go out and take a look. Admittedly, you need a telescope to see this one, and I think Gordo is the only one out there with access to one, but go out and look anyway. It's such a pretty planet. It'll be the brightest thing in the eastern sky. Take your wife, your husband, your kids, your neighbor, your girlfriend. Point it out to them. Impress them with how much you know. Maybe you'll get lucky.
Here's video of one moon shadow (Ganymede's) on Jupiter, taken with an amateur camera and telescope, no less. Imagine how cool two will look.
Thanks to the One Minute Astronomer for the heads up, and the video.