Cell Messenger is a program that sends, receives, and archives SMS messages from your mobile phone. It provides support for reading your mobile's phonebook, sending group messages, anti-spam SMS filtering, Unicode, and multipart SMS messages. It's also capable of reading a GSM phonebook into its own contact list.
f/Calc is a utility to calculate lens formulae for photographers so you can focus on the artistic bits rather than on the mathematics behind it all. f/Calc can do "f" number arithmetic, and can calculate depth of field, hyperfocal distance, the field of view of a lens, the angle of view of a lens, magnification, and how the focal length of the lens on the camera changes the way the spot metering function works. In addition to the Unix/Linux Tcl/Tk version, there are native Windows, Palm OS, and Macintosh versions as well.