Rarest videogame

The Atari 2600 videogame Gamma-Attack (Gammation, 1983) is widely believed to be the rarest cartridge in the world today, with only one copy known to exist – according to racketboy.com. Its owner, a collector from the USA, put the game up for auction on eBay in 2008 with a "Buy it Now" price of $500,000 (£325,000). However, nobody took the plunge and more recent articles in the gaming media value the cartridge at between $20,000–$50,000 (£13,000–£32,500).

Despite the game's rarity, reproduction cartridges are readily available, while you can also play it on PC. It is also reported that only one copy of Nintendo Campus Challenge 1991 is known to exist, with all other available copies having been destroyed.