Well, the whole point is to think up your own fun things. Most of these, of course, will be variations on the existing themes because there are only so many commands and things in the interface. But you can still have a lot of fun playing with different things.
For instance, did you know that the "fire asteroids at Earth" thing actually works for any type of object? Try firing another star through the solar system without aiming it at any particular body, and watch the chaos unfold. This works better with small stars if you just want planets scattered hither and yon. The supergiants are like the size of Mars' orbit so just eat everything in their path if you aim close to the middle. But that's fun, too