A very good mathematics resource: Mathworld.
An interesting mathematical page: Planetmath.

A very nice Vision page: Webvision.
A funny page full of illusions: Optical Illusions.
Several interesting resources: Serendip.

A useful OS: Linux .
RPM package resources: RPMfind.
C++: C plus plus.

Catalan governement: Generalitat de Catalunya, some general informations about Catalonia.
Catalan meteorolgic service: Meteocat (in Catalan).
Do you want to listen to some catalan radios? Catalunya Ràdio (in Catalan).
Music: RAC 105  (in Catalan).

Some hiking in Switzerland: Hiking (in French).
Swiss meteorolgic service: Meteoswiss.
Via ferrata web page: ViaFerrata.org.

Some hiking in New Jersey (USA): Hiking in New Jersey.