The Marathon, achievement in Trials HD is a bit tricky too. Think it was voted one of, if not the hardest attainable achievement of any Xbox game.
Friend of mine hacked that one 40 pointer and got his 57k reset/facepalm
Lol, i kno how hard that one is myself, but i got it legit and it took me a good 50+ tries. made me mad @ track 18 when i'd fall then have to restart lol but now i got it