Xbox Live Arcade content
Already a strong success, 360's Xbox Live Arcade download service has a handful of small-scale classics available to download right now.
But the future for the cheap 'n cheerful service is blinding: every major publisher out there is either raiding its back catalog with updates to old-school gems, or crafting whole new games, not to mention a number of smaller developers who are now able to experiment with new ideas for it without going bust. Respect.
New Live Arcade games are becoming available all the time. Really! Go look.