I've been riding my bike at Duthie Hill, which is an awesome set of trails pretty close to where I live.
They have a nice mix of XC trails that are tighter and more technical but still with some banked turns and optional features like ladders, jumps and log rides. Then, you have the freeride/downhill trails and the flowpark, which are all jumps - ladder drops, step ups, tables, gaps, ect. Additionally, there are a bunch of really short trails and individual features that you can hit over and over again, like pump tracks, lines of drops that increase in height, step-ups and skinnies, all of which are great for improving your skills. There has been a ton of volunteer work done along with some pretty good city funding and donations so it's turned out to be a really incredible place to ride.All trails are 1-directional which is great for not having to worry about people coming from the other way. The area is pretty small, only around 120 acres, but the trails are packed in everywhere:
I'm not that great, but I've been progressing well, and have been able to move on to most of the black freeride trails along with all of the XC trails. Unfortunately, I don't have a helmet cam so you can't see any of my runs (or my terrible K2 Zed 1.0 bike from 2006- who needs disk brakes to stop, pedal cranks that don't have stripped threads requiring them to be tightened every run or more than an 80 mm shock when landing, I really need to buy a new bike) but here is the website describing the trails along with a few good videos:
A video of a recent competition, the parts before this are the amateur riders and some of the guy's own riding.
One of my favorite trails, the trail is in a small gully, and you are riding up and down the sides of it, with optional drops and jumps along the way. You hardly even have to pedal because the trail is angled downwards, and you swoop down one side of the gully and perfectly sail up the other without any pedaling, go around a short corner, than repeat.
Another one of my favorites, this one has some more difficult optional routes with gaps, big drops off of ladders, and three big jumps to finish it off.
The beginner XC trail, the start has some fun stuff to do, the middle is pretty long and mostly uphill, than the finish is a series of smooth high speed banked turns, one after another.
Some impressive freeride trails, I haven't attempted these yet, and it will take awhile before I do :P
I don't know how directly mountain biking correlates to skiing, but it's definitely keeping my legs in pretty good shape and improving my confidence. Skiing next season is going to be great, as falling on dirt hurts more than on snow and so hopefully I'll have the confidence to try some stuff that I previously wouldn't have.