I have visited Las Vegas on many occasions and its always been about the casinos, shows and over indulgence. So the last time I visited (just as a stop over to Zion), the last thing I expected to do was over indulge on was some outdoor fun which extended my stay.
Red Rock Canyon is about 30 to 40 minutes from the strip. It is easily accessible and does not require overly technical skills so sturdy hiking boots with grip is really all you need. What I really love about this place is that there are less tourists as you will more likely find locals hiking the trails and almost everywhere you go the rocks and mountains scream out for you to explore and find your own path which makes for a lot of fun and explorations.
Here are some pictures of the Calico tanks trail and some of my own path finding adventures.