Xbox Live Arcade was available for about a year on the original Xbox, before relaunching with the Xbox 360. When it did, a game named Marble Blast Ultra became one of the first breakout hits on the downloadable service. It has now been delisted.
The studio behind the game told XBLA Fans that the title was removed in the confusion over who now owns the rights to it. It sounds like GarageGames was rebranded as Instant Action in 2009 and reformed after Instant Action shut down. Unfortunately, much of GarageGames' intellectual property was sold off in the meantime. That included the rights to Marble Blast Ultra. It's not even known who owns its rights.
Marble Blast Ultra sold 700,000 copies. Its downloadable content is still available on Xbox Live.
Marble Blast Ultra delisted (UPDATED) [XBLA Fans]