Video and instructions at http://www.instructables.com/id/Music-Playing-Alarm-Clock/
I know most of you will simply glance at the first page and maybe skim through the rest. This Instructable has 18 steps (with demo examples for each building block) and 5 appendices, with about 90 files and pictures, including logic analyzer files/screencaps, expected terminal output, USB device dumps. I sincerely hope you explore all my efforts. I covered everything from SD cards, FAT file system, USB mass storage, IR remote control, LCDs, RTCs, and decoding MP3s. It's built using a Teensy++ and encased into a SparkFun shipping box.