I've ridden a number of "world class" trails, including Hermosa Creek, Monarch Crest, Thunder Mt., South Boundary Trail, but Phil's World is the absolute most  fun ride I've ever been on. Well laid out, flowing, scenic, not too technical, just fun.  The premier fun spots are " The Vertebrae" and "The Ribcage" which are like riding the roller coaster on your bike.

This trail is all singletrack and if you make all left turns at the intersections, you will ride the entire loop.  You'll cross some doubletrack, but remember, this trail is ALL SINGLETRACK, so don't turn onto any of the doubletrack. I can see your big grin now!