PostgreSQL is a robust relational database system with over 25 years of active development that runs on all major operating systems. It is fully ACID compliant, and has full support for foreign keys, joins, views, triggers, and stored procedures (in multiple languages). It includes most SQL92 and SQL99 data types, including INTEGER, NUMERIC, BOOLEAN, CHAR, VARCHAR, DATE, INTERVAL, and TIMESTAMP. It also supports storage of binary large objects, including pictures, sounds, or video. It has native programming interfaces for C/C++, Java, .Net, Perl, Python, Ruby, Tcl, and ODBC, among others, and exceptional documentation.
Powertweak-Linux is a tool to tune your system to its optimal performance settings. It started life as the replacement for the now obsolete kernel option 'tune PCI bridges', and has been extended to provide more features and support more chipsets. It can also tune network/filesystem performance using /proc/sys entries, disk elevator settings, and x86 CPU registers (needs 2.2.18 or 2.4.0test kernel), CDROM speeds, hdparm type features, and Sony VAIO backlight. It has both a GTK GUI and a text-based lister.
PPP Keepalive is a perl script intended to maintain a persistent dialup connection. When the script redials it can then send an email containing your dynamic IP address to an email account or ftp the address to a server. This way you can obtain the current IP address for your box remotely. This also introduces security issues, so use at your own risk.
pppctl is a suite of programs suitable for use by those with ppp connections. It includes programs to facilitate charging for use of the connection, controlling the connection from a web page and selecting from a range of ISPs to use to dialup. It's also ideal for doing automated mail/news polls.
PPR is a Unix print spooler expressly designed for operating PostScript printers. Its features are numerous, and it supports printers connected to parallel or serial ports, or over the network through AppleTalk, LanManager, LPD, and TCP/IP protocols. It accepts jobs from Microsoft Windows, Macintosh, and Unix clients. If the input file is not PostScript, it can pipe the input through a filter. PPR has been designed to manage large numbers of printers with minimal operator attention. It has command line and Web interfaces.