Some people might look down on the loop but everybody has ridden there at one point or another. It's a great place for people to practice basic mountain biking skills and a convenient ride for locals. You won't get the 'true' mountain bike experience since the loop is a system of trails spread out across a city, but it's still fun.
See if somebody will ride with you the first time out, the ride is a bit confusing at first but very easy to remember once you've been on it.