If you followed my other (tiny) tutorial on creating a mediacenter then you should now have your PC linked to your TV.

If youre a fan of Singstar and similar games for the consoles, then you may like this... An open source (free) karaoke game for your pc!

A free and open source karaoke game inspired by the Singstar game available on the Playstation. It allows up to six players to sing along with music using microphones in order to score points, depending on the pitch of the voice and the rhythm of singing
Download

Windows

UltraStar Deluxe Installer (10 MB) (If youre not sure, use this one):
With possibility to download 40 songs and some additional themes
UltraStar Deluxe ZIP (22MB) - With three songs and additional themes
UltraStar Deluxe ZIP Lite (13,6MB) - without songs and extra themes
Linux / Mac OS X

There is no pre build package available yet, but this version is known to work well in Wine - a tutorial can be found in the USDX Wiki here.
Links of interest

Linux getting started guide - Forum thread
Linux compiling guide - Wiki
Mac OS X Snapshot version - Forum thread with dmg file
Mac OS X the actual progress
- Forum thread
Mac OS X working UltraStar - Eddie (the author) has joined our team, this his old project (NonDeluxe!)
Additional Content

Themes - More Eyecandy
Plug ins - For more game modes in the party mode
Songs - Different songs either released under Creative Commons licenses or where the project obtained the permission to distribute them