All gamers have one - whether it possesses fond memories or you just like to play it over and over again, there's that game you can never part with. What you may not know is you could be sitting on a fortune.That's right, some games have a little more than sentimental value, they are worth a lot of money. Gamers have always heard of rare games like the 1990 Nintendo World Championships cartridge, which appears on the top 8 list. DualShockers looks at the Top 8 of the most rare and expensive games in no particular order:

Stadium Events (NES) Price Range: $13,000 -- $41,300; $10,000 for the box alone

Originally released by Bandai for their Family Fun Fitness mat, the rights were later purchased by Nintendo. It then became World Class Track Meet for play on a little something we call the Power Pad. Nintendo wanted this to look like a first release item, so they had all copies of Stadium Events removed from stores and destroyed, except 200 cartridges that had been sold. Hence the game being worth so much. Only 10 to 20 copies are believed to exist today. The game has been sold on eBay two times recently. One by a North Carolina woman sold for $13,105. Think that's alot? A Kansas man found a factory sealed copy, one of only two known to exist, and it sold for an amazing $41,300. The irony of it all is, the rereleased Nintendo version World Class Track Meet, sells for about $3 on eBay.

1990 Nintendo World Championships (NES) Price Range: Gray: $4,000 -- $6,100; Gold: $15,000 -- $21,000

The Nintendo World Championships featured a winner takes all tournament held in 30 cities. Contestants played Super Mario Bros., Rad Racer, and Tetris with a 6 minute time limit for each. At the end of each cities' competition, the top player in each of the 3 age divisions was given a gray game cartridge that was used in the tournament. Which basically means that there were only 90 given away. And if you were a lucky winner who participated in the Nintendo Power Magazine and won, received one of the gold cartridges. There were only 26 produced, so you can imagine why they would be worth so much.

Nintendo Campus Challenge (NES) Price Range: $14,000 -- $20,100

Luckily, this type of contest is still held by GameBattles and other companies. But in the early 90's Nintendo was king. A competition held on campuses across the Nation and at popular Spring Break destinations gave gamers again 6 minutes to gain the highest score they could. The 3 games this time were Super Mario Bros. 3, PinBot, and Dr. Mario. All copies of the cartridges were destroyed after the competition. Or so they thought. An employee of Nintendo saved his copy of the game and sold it in a garage sale with other Nintendo items for $1,000. The man who purchased it later resold it on eBay for $14,000 and is still the only copy known to exist in the world.

Atlantis II (Atari 2600) Price Range: $5,000 -- $6,000

What makes this game so valuable you ask? Atlantis, not Atlantis II, was released in 1982. Still haven't heard of it have you? The developer of Atlantis held a contest that year. Gamers would take pictures of their high scores and send them in. Your prize? A copy of Atlantis II which featured a faster type of game-play and a harder scoring system. The company figured that was the only way to prove who the real champion was. There were very few copies of the game produced. The kick is, if you have it you may not even know. The only difference in the cartridges of the two was a small white sticker on the cover of the original which said Atlantis II. If you happen to own a copy and you don't know which one you have, a quick Google search can help you out.

Air Raid (Atari 2600) Price Range: $1,000 -- $3,000

The information is confusing on this particular game. Why, you ask? Mainly because the cartridge doesn't even say what the game title is. The game play is similar to Missile Command and Atlantis. The developer was a company called Menavision (Menovision), depending on who you ask. There are 2 reasons the game is worth so much other than nobody really knowing it's name. The first, it comes in a T handle blue cartridge which was primarily seen in Brazil. And second, there are only about 12 copies that exists.

Star Wars Ewok Adventure (Atari 2600) Price: $1,680

Being a Star Wars fan myself, I was intrigued to see this game on the list. Basically because I never knew it existed. The game was originally developed back in 1982 and packaged as Revenge of the Jedi: Game 1 by Parker Brothers. It was also known as Ewok Adventure due to the main character being an Ewok. The premise of the game was an Ewok would fly its glider and try to destroy an Imperial Base on Endor. The player would try attempt to be stopped by Stormtroppers, Speeder Bikes, and AT-STs. The cool part of the game was the player could have their Ewok take control of the vehicles to help them in their quest to destroy the base. The game however was never produced due to Parker Brothers' marketing department feeling the game's controls were too difficult for young gamers. The designer of the game, Larry Gelberg, later gave the only prototype to his son's friend. It was later sold for $1,680.

Kizuna Encounter (Neo Geo) Price Range: $12,000 -- $13,500

Kizuna Encounter, a 1996 fighting game in the mold of Mortal Kombat or Street Fighter, is one of the most sought after games for collectors of Neo Geo games. The version of the game that is worth the most is the European version, of which only 15 copies were made. The Japanese version, which has different packaging, is common and only sells for $50. So Japanese fans if you have a European copy laying around somewhere, get it out and sell that puppy. Keep your copy for yourself.

Ultimate 11 (Neo Geo) Price Range: $8,000 -- $10,000

If your a Neo Geo fan, and more importantly a soccer fan, then Ultimate 11 was the game for you. The last in the Super Sidekicks series, Ultimate 11 is highly coveted due to there being only 10 copies in existence. The game was sold on the collector's forums at neo-geo.com with Kizuna Encounter for $55,000. The collector who purchased the game was quoted as saying he would never sell the copies even if he was offered $100,000 for them. My ultimate goal is to find this man and become very good friends with him!

So there you have it. A list of games that are worth a crazy amount of money. So get to looking in your garage and attic for that one game that may or may not be worth a ton of money. And the next time your at a garage sale, be sure to keep your eye out, you never know what you might find.

info via CNN