I like to go to Disney Quest when it opens in the morning, and stay for a few hours. When I was there in August, the people I was with wanted to go in the evening, and it was very busy, long lines for everything. I would suggest avoiding Disney Quest on Friday and Saturday nights.
Some of my favorite things to do at DQ are:
Cyber Space Mountain--you design a roller coaster and go in a flight simulator to ride it. Lots of fun.
Virtual Jungle Cruise--You sit on a raft in a gigantic air pillow, and guide yourself down a river. This is the most fun if you have at least three people because you can make your raft go better.
Buzz Lightyear Astroblasters--Bumper cars with a twist. You have to shot asteroids (kick balls) at the other cars, and if you hit the target, the car goes spinning.
Pirates of the Caribbean--You stand in a ship, and have to shot cannons at ghosts ships. The line for this is usually very long. It's great, but I usually don't bother waiting in the long line for it.
Have a great time!
Karen