Although sales of rhythm-based music games are on a steep decline and the "Guitar Hero" franchise is, as of February 2011, officially dead (see gameinformer's coverage and commentary here), that hasn't stopped related lawsuits from proceeding. The pop-ska band "No Doubt", in particular, has been embroiled in a longstanding legal dispute with publisher Activision due to an alleged misuse of the band-members' likenesses in Band Hero, a lukewarmly-received Guitar Hero spinoff. More recently, Activision responded by moving to strike the proceeding on freedom of speech grounds, but the motion was denied. Activision ultimately appealed, but in a recently ruling, an appeals court upheld the decision of the trial judge to deny the motion.
Further details here, and case citation below.
No Doubt v. Activision Publishing Inc., 2011 WL 507479 (Cal. Ct. App., 2d Dist. Feb. 15, 2011).