Unfortunately, I have no idea what the game is nor do I know of the makers, but just because I'm curious, what was the reason behind the hiatus?
Rock Band is basically just another version of Guitar Hero except it lets you "play" instruments other than the guitar, like piano and drums.
I have The Beatles Rock Band just sitting atop my wardrobe collecting dust. Really should get back to playing that (and GH) also. YAS I'm so there!
It's a touch more complicated than that. After Guitar Hero II, Activision bought Red Octane, who owned the Guitar Hero IP. Harmonix, who had developed the first two games, still had the rights to use the code, so they started Rock Band due to being booted off Guitar Hero so Activision could give it to Neversoft to churn out yearly (or rather, three or four times a year since Activision published FOURTEEN Guitar Hero games in the span of four years). Harmonix, being a company made up of musicians and specializing in rhythm games, made a MUCH better game with any Rock Band title than any of Neversoft's Guitar Hero outings.