The Aria is well-positioned to explore the entire Strip. Other than the usual sights and sounds of the Strip, I suggest the following:
Go to the EIFFEL TOWER RESTAURANT at Paris and sit at the bar at sunset and enjoy a drink while watching the lights of the Strip come on as well as the Fountains of Bellagio. (You need reservations for dinner but can go up to the bar for a drink without a reservation. Great cocktails. Smart casual attire only.)
Go see MILLION DOLLAR QUARTET at Harrah's. Harrah's is a lousy casino, but this show is definitely worth seeing (unless you've seen it before, lots of incarnations of it around).
At Caesar's Palace (the best casino in Vegas), there is a shopping area called The Forum Shops. Several nice dining places, cool shops, and stick around for the show on the ceiling which is enchanting.
Do not miss walking through both Wynn's and Encore. The entrance areas and casinos to both hotels are beautifully decorated. WAZUZU is a great Asian restaurant in Encore, one of the best meals you can have in Vegas which is not known for great food.
Of all the Cirque du Soleil shows on the Strip, I still like MYSTERE the best.
Skip downtown completely.
Off the Strip:
Other than Hoover Dam and Grand Canyon which you have mentioned, VALLEY OF FIRE STATE PARK is 50 miles north of Vegas. It's a nice hiking park, but you can also access it on park roads in your car. It's an interesting look at the red sandstone formations in the area and has some ancient petroglyphs also.
Whatever you decide to do, have fun!