The 260-acre (1.0-km2) park lies on a hillside west of interstate 5, which runs north-south through Valencia. Take the Magic Mountain/McBean Parkway exit in either direction and follow the signs to the park.
Six Flags Magic Mountain - The flagship park of the Six Flags franchise of theme parks, Magic Mountain is currently the largest roller-coaster park in the world, although this record tends to see-saw between them and Cedar Point in Sandusky, Ohio. If you are planning on going to Magic Mountain, plan to spend the entire day. The park is open weekends & holidays thoughout the year, and open daily from Memorial Day though Labor Day. Admission price is about $50 per person. Parking is another $10.
The gift shops and eateries in the park are not cheap! Expect to pay very high retail on trinkets that are "customized" merely with an imprint of the Six Flags moniker. The quality of the food is comparable to fast food fare, and you can expect to spend 20 USD for lunch for two not including drinks. The cost is partially justified as an offset to maintainence and development costs.
Doc's Inn, Somewhere on Lyons Ave. Be wary of the mid-weekers.