Here's a link to an article that mentions them...

http://www.casinoman.net/content/news/newstemplate.asp?artid=1113

...Rocket Games, a bingo game maker owned by the Miami Tribe of Oklahoma, sells electronic bingo games in about a dozen states but wants to expand further.

The company is eyeing states -- including California -- where tribal casinos have compacts that prevent them from adding more slot machines, said Nelson Johnson, chairman and chief executive officer of Rocket Games.

Bingo machines are less lucrative than slots but offer an alternative that isn't restricted under state compacts, Johnson said.

"We want to fill in the gap between what (the tribal casinos') market will bear and what they're offered under the compact," he said.