Links
Dartmouth Open Source Community
Mathematics at Dartmouth CollegeGNU Multiple Precision Arithmetic Library
NTL: A Library for doing Number Theory
Project LinBox: Exact computational linear algebra
Valentino and friends picture site
DVD Region+CSS Free If you use windows and you want to use standard certified DVD player (both cases shame on you) and you want to watch both american and european DVDs then DVD Region+CSS Free is what you need. Anyway, I would never buy for something I can have for free.
Daemon Tools This driver (for windows) will make your computer believe that the images of cds on your hard drive are actually real cds so that you will not need to bring the original copies of your programs and games across the ocean. It just works.
Dizionario Oxford-Paravia The electronic version of this italian-english dictionary (only for windows) is the best and most usable electronic dictionary I have ever found. The only thing missing is the phonetic spelling.
Macmillan english dictionary This is the best english learning dictionary (only for windows) that I know. It contains almost any english word ever written down together with its phonetic spelling