BASIC-BINARY-IPC uses local or network (IPv4) streams for inter-process communication. It supports fast multiplexing primitives on multiple platforms, e.g. epoll (Linux), kqueues (OS X and FreeBSD), and overlapped I/O (Windows 8). (The author seems too modest, because that's well beyond "basic.")
CL-STRIPE-CLIENT is exactly what it sounds like: a CL client for the Stripe online payment system.
Last week I asked for suggestions to rename ASDF 3.1's "package-system" feature. Jean-Philippe Paradis came up with package-inferred-system, and the change was committed in ece9fa3205875fdf88122554abf73e6af6d402b9 on April 19th.
cmacro adds Lisp macros to C source with a preprocessor written in SBCL. It sparked some lively discussion on reddit.com/r/programming.
neslisp-c64 is a port of neslisp to the Commodore 64. (I can only assume that hosting it on SourceForge is in that same spirit of retro nostalgia.)