If you want to go for a dinner that both the adults and the kids will like, try going to BLT Burger (
http://www.bltburger.com/) in The Mirage. There are tons of choices for burgers - I got the Wagyu beef burger - and the milkshakes are out of this world good. Plus they have a really good beer selection. I highly recommend this place.
The Harley Davidson restaurant on the strip has really good food with big portions and pretty reasonable prices.
Edit: I just noticed you said no kids. If you want a really nice dinner, go to Bobby Flay's Mesa Grill in Caesar's Palace. It's a bit pricey, but well worth it. Probably one of the top 3 meals I've had in my entire life. I had duck breast with carrot habanero sauce and a chili rellanos for an appetizer. Phenomenal food. Even without the kids, I would still recommend eating at BLT burger.
I saw Ka when I was last there, and it was amazing. Well worth the money.
If you want to see a comedy show, you could go see Carrot Top in The Luxor. I heard it's actually a really great show, and not too expensive. Get the tickets for it at one of the Tix4Tonight booths.
http://www.tix4tonight.com/. There's one across the street from the Mirage, beside the Dennys. They open at I think 10am and there's usually about 30 people in line.