Released back in 1984 by Lucasfilm and published by Epyx, Ballblazer didn't foreshadow the company's classic adventures, but does remain a fun and technically impressive futuristic sports game that's both collectible and historically significant. It was after all the very first game developed by Lucasfilm.
Also, here's a lovely Ballblazer eBay auction. It's all about a well preserved boxed copy of the game, that comes complete with its manual and the double-sided disk that will let you run it on either an Atari 8-bit micro or the Commodore 64. Seller ships worldwide.