Passo dello Stelvio is best ridden West to east and in the morning before all the caravans clog it all up. The Stelvio one of the most famous biking passes in the Alps- and the 2nd or 3rd highest at 2758m, depending on who you believe.
 
Winding up from Bormio, the western ramp has very nice surface, great corners, and stunning scenery. If it is clear, a stop at the top is almost mandatory, you can even do some summer skiing if you want. The east ramp is hairpin city, but again, stunning scenery. The very steep and tight hairpins make this a difficult route, especially if you are on a big or loaded bike. Once you clear what seems like a endless number of hairpins, the road opens up again and provides some great riding.