mxallowd is a daemon for Linux Netfilter (using libnetfilter-queue) and BSD pf (using pflog) which implements a slightly improved nolisting mechanism. It requires your name server to be configured to return two MX IP addresses, and the one with higher priority must not run a mail server on port 25. mxallowd blocks attempts to connect to the mail server unless the sender tries to connect to the first mail server before the second. Since most spammers will attempt direct connections to each mail server, they will be blocked.
Das Schaefchen is a lightweight HTTP server and proxy for Unix platforms. It supports the minimum requirements of the HTTP/1.1 protocol and virtual hosts, basic authentication (which can be used to protect either files or directories), directory listing, byte ranges, reverse proxy, and FastCGI. It is an event-driven server that runs as a single process with a single thread using non-blocking I/O. It uses epoll as the event notification mechanism to multiplex control between active connections.
elfrc is a program which can turn arbitrary files into ELF object files which can then be linked into your program directly and accessed via simple, user-defined symbol names. Since this is much more effective than turning a binary file into a C array and then compiling that, it's possible to embed even huge (a few hundred megabytes) files directly into the executable and then access the data in constant time without making the compiler or linker eat loads of memory.
libburnia is a project comprised of libraries and binaries for reading, mastering, and writing optical discs. It provides libburn, a CD/DVD/BD burn library, libisofs, a manipulation library for ISO 9660 filesystems, and libisoburn, a ISO 9660 multi-session library. On top of them there is cdrskin, a cdrecord emulator, and xorriso, a all-in-one application for ISO 9660 multi-session operations which additionaly provides a limited emulation of mkisofs.
Callweaver is a community driven software PBX project. The most important differences between Callweaver and Asterisk are built-in STUN support, the use of SpanDSP for better codecs and full T.38 fax over IP support, Sqlite instead of Berkeley DB, universal jitterbuffer, POSIX timers to avoid Zaptel timing dependencies, greater speed, more efficient dialplan execution, and greater stability.