Read more in “Sega's Sonic the Hedgehog Turns 20, Joins Nintendo's Mario for London 2012 Olympics Video Game.”

June 23 marks the 20th anniversary of Sega's beloved mascot, Sonic the Hedgehog. Beginning today, gamers can download demos of Sonic Generations, the anniversary game, via Xbox Live Arcade and PlayStation Network . The demo, set in Green Hill, will be available for the next twenty days, according to a recent press release.

Classic Sonic; Credit: Sega

Classic Sonic; Credit: Sega

Sonic Generations features the iconic video game character in both classic and modern form traveling through a variety of different levels, both 2D side-scrolling and 3D ones, that recall the hedgehog's adventures over the past two decades. The game won't be out until the holidays, when it will be released for Xbox 360, PlayStation 3 and Nintendo 3DS.

Sega will be celebrating this milestone all year. During E3, fans were invited to demo Generations at Club Nokia, where they also had the opportunity to party with Sonic's creators and take in a live performance from Sonic-affiliated musicians. Later this year, Sonic will be making a special anniversary appearance in the Macy's Thanksgiving Day Parade.

LA Weekly