This post is all about arguably the most addictive video game I have every played (yes, even more than Fable 2) & it's called Trials HD.
Originally just an Internet game, but envisioned to be something much more smooth & intuitive when using the xbox controller system. It's a an amazingly simple premise - guide a bike & rider though a series of tracks (platform style) using 4 controls only; power, brake, lean forwards & lean backwards.
But the tracks, that's the hard part - things start simply enough, but an impressively fast learning curve is the order of the day - things start to look more & more impossible - how is it possible to do a standing jump of 20 feet & not hit the floor - no idea!
So to help you...slightly, there are a series of unlockable bikes with more power (or in the case of my favourite monkey bike - silliness!) ratios which help you power of some chasms, etc.
Even if you manage to conquer the beginner, easy, medium tracks, then there's also hard & extreme to give you some nice impossible ones to try your hand at - overall there's 50 tracks. Then more, if necessary, in the shape of some DLC (more coming soon) so new tracks & challenges.
Oh yes, there are some challenges as well - as if the tracks weren't hard enough - there a load of specials designed to get you even more addicted: ski jumping (on a bike) ride a giant cage ball (inside & out) use your bike with a rocket pack on it, giant bike pinball, pull a wheelie with the front wheel falling off & many more.
It's 1200 MS points (about £10) but you can get a demo version for free of course! It's the best thing I've seen on Xbox Live so far & it's super addictive a well worthy addition to any gamer's collection & surprisingly the more alcohol content in your blood, the better you drive - super-epic-win!! Check it out here over on Xbox Live
PS & if you feel really keen, you can do tournaments - multiple tracks where your overall time dictates how well you do - epic