If you need a quick escape from all the glitz and gambling of Vegas this is a great option. The Lake Mead National Rec area is just a short drive east of Vegas and offers boating, fishing, hiking and beautiful scenery.
There are several entrance and exit points so check the official website for directions and information. There is a $20 entry fee but it is valid for 7 days. There are marinas to launch your boat or if you want to rent a boat, wave runner or house boat they are all available.
There is tons of information available on the National Park website for additional information or ideas. Enjoy the day away from all the hotels and people.