I've lived in Las Vegas for 8 years and visited Adventuredome for the first time on Labor Day. Our relatives were in town with 10 year old boys and this seemed like the perfect place for them to burn some energy and have fun while the grownups chatted.
For a holiday it did not seem packed. Prices were kind of high, but that can be expected from any casino experience. Go for the day-pass. BOGO coupon in the 2011 Entertainment book. Kids and adults can ride the rides. I didn't partake in any rides, but they seemed average for that size amusement park. The kids had a BLAST and parents seemed to get their value from the price. There were plenty of places to "park your booty" while the kids waited in line and rode the ride.
They have carnival style games which are fun but basically a $$ trap. Food and ADULT beverages available inside (yay for booze mixed with rides and kids). Watch out for the drunky adults.
I would take my kids here, but not on Saturday or Sunday.