Woods Canyon is riddled with tons of great technical trails. The Woods Canyon Trail is a fireroad that runs the length of the park and connects to the majority of trails. This is a great place to start. At the bottom of many of the descents you will find yourself in business parking lots. Either turn around and head back up the way you came or ride around a bit and you'll likely find another trail to explore on your long technical climb back up. This is a popular hang out for several pro riders like Brian Lopes, Shawn Palmer, etc. Also Hans (No Way) Rey lives nearby so is often seen hopping around the park.
How to get there:
Take I-5 to Alicia Parkway, turn SW. Take Alicia Parkway for a few miles past Aliso Creek Road. Just past the road on the right side is an entrance to a Mormon church and the entrance to the parking lot. Parking fee is $2. Trail starts beyond the locked gate.