The following links lead to sites which I like to visit myself. Most are bike related some are not. I will take no responsibility about the content of the sites.

Pizzacup (Swiss German, German)

The not so street illegal race series in Zurich since 1996. A few idealists and shop owners gathered together to race in the woods around Zurich. The winner got a pizza for free. Many events mushroomed around the Pizza Cup, such as Bike video premieres, best bikes contests or used parts markets. Most of the ‘seniors’ are still very much active, and most of the original bikes hops are still around!

MTBR (English)

One of the best resources concerning bikes and associated material. You can find all possible bike parts and respective reviews and information about them. Even vintage pieces are listed. In addition to former info, you also have all news concerning international competitions. You can also take part in Form discussions. The info is very US-related, but let’s face it: Most material is from there!

Weight Weenies (English)

If you are concerned by the weight of the pieces you want to mount on a bike, you can browse through this site. You can access a parts list with real measured weights and their comparison with the weights stated by the manufacturers. You can imagine that there are some discrepancies! If your bike is super light you can post pics and description, there is even a ranking of the lightest bikes.