VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
foobar2000 - An advanced freeware audio player for the Windows platform.
Digital Clock 4 - Beautiful customizable clock with plugins
Winamp - Winamp is a media player that allows users to play multiple-file formats, arrange media in a varied file-management system, and play unique media with AAC encoding.
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.