Reddit user FightAnArmedBearP started a discussion titled "Should my startup attempt to use ABCL in a production environment?" The ensuing feedback from Mikel Evins, Cyrus Harmon, Mark Evenson, and others is of extremely high quality, with excellent information about using ABCL and other solutions for working with Lisp on the JVM. Highly recommended reading even if you think you'll never be in the same situation.
cl-autowrap by Ryan Pavlik looks to me like a genius way to do FFI wrappers without needing to use stub C programs and a compiler at build time. It uses c2ffi, a standalone C++ program, to generate specification data files you can distribute with your project, after which neither c2ffi nor a C compiler is involved in using the FFI wrapper. It's a work in progress, one of the Lisp In Summer Projects projects, but I'm excited about the potential.
Speaking of Lisp In Summer Projects, Janne Nykopp's Notewhacker sounds fun: it's a game for learning sheet music notation, with MIDI instrument support.
elPrep is a LispWorks-olnly, BSD-style-licensed "high-performance tool for preparing .sam/.bam files for variant calling in sequencing pipelines." I don't know what that means, but it's a full Common Lisp application for the purpose, and it looks neat. From Charlotte Herzeel and Pascal Costanza.
Ezra Rush has written networked, OpenGL battleship and pong games. They use Patrick Stein's userial game protocol example.
Slugmage is a work-in-progress game from Alyssa Carter. "I hope to turn Slugmage into the game it was meant to be!" Uses SDL.
Testament of the White Cypress is "a fantasy role-playing adventure game for your Windows, Mac, or Linux PC. Using the mouse and keyboard, a single player controls a lone monk named Geoffrey as he travels through a post-apocalyptic wilderness." From David O'Toole, using his Xelf game engine. It has split licensing: the code is GPLv3 but the music and art assets are not freely redistributable.
Nicolas Hafner takes a shot at explaining CLOS to the uninitiated.
site-generator is a "command-line static site generator that supports arbitrary content and multiple languages." By Alex Charlton. (Not to be confused with Philip "Don't Call Me Phil" Greenspun's SITE CONTROLLER.)
qlot by Eitaro Fukamachi is a project-local library installer that uses Quicklisp. "This aims to be like Bundler of Ruby or Carton of Perl." Seems interesting, though it comes with a big "ALPHA quality" warning.