RollerCoaster Tycoon, the best theme park simulator I've ever played. Even with it's dated graphics and above average music, it's still amazing.
The point of the game is to accomplish your goals in the parks you're given. Simple? Perhaps, but the game holds a great amount of fun to be had. It revolves around building rides and shops to satisify your guest's needs. It may sound boring but give it a hour or 2 and you'll be hooked. The rides come in a variety, from the wussy gentle rides like the Merry-Go-Round to the money-making Go-Karts. The variety is amazing and for most of them, you can design the tracks.
The best part is designing RollerCoasters. The game includes over 10 different types and some built in ones that are actually pretty good. Each type can be built to a certain height and just seeing the high excitment rating for the ride that you just created is a great accomplishment. The rides cost money, which comes from other rides, shops and the park entry fee. The fiancial aspect of the game is handled excellently and is easy to use. The game (and guests) even comment if your rides or entry fee are too cheap or too expensive.
The graphics are dated but were great in it's time. The game never slows down and watching the RollerCoasters in motion is amazing. With all the people and rides/shops in the park, it doesn't even get hard to see them all thanks to the zoom and map rotation features.
The sound suits the game with the music for the rides, the guests screams when they go on the Roller Coasters and the toilet flushing.
Since the game is old, it could be a bit tricky to find and it should be played with it's 2 expansion packs. The game is loads of fun for the casual and hardcore gamer who has patience to see their park rise from a small-time place to a profit generating theme park.