Those Nintendo NES games you got for Christmas back in the day could be worth a lot of money. Collectors will happily pay up to four figures for the rarer cult titles: for example, a factory-sealed example of the original Castlevania game can comfortably sell for up to $1,600 (£1.3k), while fans on eBay have paid up to $2,175 (£1.7k) for a factory-sealed version of Mario Kart 64.

A particular cult classic, this Mega Man X2 Super NES game from the 1990s is especially rare and collectors will go to great lengths to snap up a copy, especially if it's in mint condition. In fact, a factory-sealed example once sold for $5,100 (£4k) on eBay.

Childhood Christmas gifts that are now worth a fortune