I remember flying around in space in non-lucids mostly. It's pretty easy, but it's scary for me since I always feel that the sensation of floating around, and with random things that might occur would prevent me from having a decent exploration. There was one dream where I was viewing a Star Trek type of space-ship with a Starbucks logo on it.

Then I recall one more dream where I wanted to travel through the solar system and pick a planet, and I ended up going to Neptune. However, because my mind made the planet mostly water-based, it scared me to death since I hate any dream where I'm deep underwater. And one more dream from the top of my head is that I jumped really high from Earth, floated around space for a bit, and then shifted myself a bit to move a few hundred miles from my initial point in the dream as I was falling back into Earth again.