If RPGs are your think then look around for RPG Maker 2k/2k3/xp. Some people consider them warez, but seeing as they were never released outside of Japan and the english versions were made by fans, I don't think you'll get in trouble for using it.
If point and click adventure games (a la Space Quest, Monkey Island, Leisure Suit Larry

) are your thing then check out Adventure Game Studio (
http://www.adventuregamestudio.co.uk/ )
If 3D games (FPS, 3PS, etc) are your desire then check out Reality Factory a very nice Open Source toolkit that lets you make simple shooters without writing a single line of code and complex 3d if you learn the simple scripting language.
If retro systems are your hobby, then check out SEUCK for the C64. Although if you're actually in 8th grade you prolly don't know what the C64 is...
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