If you have an hour or two to burn, the Red Rock Canyon visitor center and scenic drive are worth a visit for the $7 (per car) admission fee.
The visitor center has information on the geology, habitat, and animals that live in the area displayed through videos and indoor and outdoor exhibits. Pets are not allowed inside the visitor center but you can walk to the outdoor exhibits with them just fine.
Once you're done with the visitor center, get in your car and begin the 13-mile scenic drive where you'll see multiple stops to take photos. Each stop has a few parking spots to pull into, take photos, and then continue on your way.
This was a fun and relaxing place to go with my wife and puppy because we wanted something away from the hustle and bustle of the Strip.