Linux + Kursunterlagen
Winzig is a suite of PIM style applications written in Python/GTK. It works not only on the Nokia 770 but also on desktop Linux installations and even on Windows.
otpCalc is an RFC2289 and RFC1760 compliant OTP and S/Key calculator, usable for example to generate one time passwords to authenticate against services running OPIE (English mini-HowTo #1 and #2, German HowTo).
If an application doesn't show up in the Nokia 770's task navigator, the reason is usually it's missing or wrong StartupWMClass setting in the .desktop file, usually found somewhere in
/var/lib/install/etc/others-menu/extra_applications/<application>.desktop
Luckily, finding the proper setting is usually rather easy:
Playing old Lucasfilm Games (or Lucasarts) classics like Monkey Island or Zak McKracken on the Nokia 770 was my favorite over the holidays, thanks to the great ScummVM port by Tomas Junnonen.
Unison is a great tool to synchronize files between different computer systems, supporting various UNIX platforms including Linux and also Microsoft Windows.