If you can't find something to do for a week in Vegas, then you're in the wrong Vegas. All these things can be done without gambling a penny: Hoover Dam, Red Rock Canyon and/or Valley of Fire State Park, shows (pick your pleasure, there are plenty), roller coasters (check out the one in Primm as well), MGM's lion habitat, I think Mandalay Bay has a good aquarium, Richard Petty Driving Experience at Las Vegas Speedway, clubs (Hard Rock has some good ones I hear), there's this wacky "indoor flying" experience I saw on TV, M&M World (I want to see the movie) and Sega Gameworks, Wet and Wild waterpark. You can get "married" again if you want. We're doing the drive through for giggles next time we go (where HHH and Stephanie got "married" if you watch wrestling).
The list goes on - I'm sure I didn't list anywhere near all of them. I've been there twice (7 days then 4 days) and we haven't done all the things we want to do yet, and nothing's been done twice. Sometimes just people watching is more fun than anything else you can do down there.
Actually September is a decent time to go. It shouldn't be blistering hot still (maybe?) but the rest of the country hasn't turned to winter yet, so less people are trying to hide from the snow back home.
Oh yeah, and the Grand Canyon is ~6 hours away by car. A friend went there for his honeymoon. Dress warmly - it was May and he was wearing shorts and was very underdressed.
