Background

Guitar Hero, first released in 2005, is a series of video games developed by Harmonix Music Systems and later Neversoft, and published by Activision. The game allows players to simulate playing the guitar parts of famous rock songs using a special guitar-shaped controller. The game series has been extremely popular, including influencing the music industry, and has expanded into many spin-off titles such as DJ Hero or band-specific titles Guitar Hero: Metallica. Since then Harmonix, having been bought by MTV Games, has gone on to develop Rock Band, a similar themed series which add in drums and vocals, which has also proven successful.

Two memes relating to the names of these games have since developed.

"X Hero"

The first involves the juxaposition of the name "Guitar Hero" with other instruments or tools, resulting in a humorous joke, typical in the form of an image or comic. These would typically include description of the fake game's features in line with the actual Guitar Hero game, and often a logo using sharp-edged fonts found on the game's actual logo. Numerous web clothing vendors have shirts featuring one or more of these juxapositions. One of the first appearances was Gamespot's April Fools' announcement of "Cowbell Hero", parodying at the time the recent "Gotta Have More Cowbell" skit from Saturday Night Live. A video based on "Osaka" (Ayumu Kasuga) from Azumanga Diaoh playing "Cowbell Hero" appeared in the anime music video, AMV Hell 4.

https://www.youtube.com/watch?v=QlqLLZQLNiA

In The Simpsons Game, one virtual ad shows "Sitar Hero", with Apu Nahasapeemapetilon playing a 20-button sitar controller; Harmonix reportedly was happy with the parody.

The "Hero" has been referenced in both print and web comics:
From Penny Arcade

From FoxTrot

The Onion carried a satirical story about Sousaphone Hero

Microsoft has released an add-in for it's Office 2007/2010 products called "Ribben Hero", a "game" structured around helping users to become more proficient at using the functions of the updated software, with Guitar Hero-like score and achievement tracking.

"Guitar Hero: X" / "X: Rock Band"

The second meme arising from the games is the addition of any band name before or after the title; for Guitar Hero games, this is after the title (in the same manner as Guitar Hero: Metallica) while it is before the title for Rock Band games (ala The Beatles: Rock Band). Such humorous names are designed to make fun of artists or bands that would be very unlikely to have a dedicated game to them due to their style of music, to make fun of the band in general, or to poke fun at the games themselves. Harmonix has used this themselves: in the development of their new Rock Band Network, a means for artists to create and distribute their own songs with the game, they reported named the project Rock Band: Nickleback to prevent any significant inquiry from the press.

A spoof of Guitar Hero: The Beatles poking fun at Activision's approach to band-centric games:
https://www.youtube.com/watch?v=Fry-oxfDM8I

Rock Band: Oasis from BBC:
https://www.youtube.com/watch?v=yw-delgGVmw