ok, there is a game called WoC (War of Conquest) that is pretty fun, pretty much you start out as a primitive nation that have to defeat other nations to grow in strength and tech. and the Tech system is pretty cool, it sets you out with a base couple of techs to chose from for your next level, and when you gain a level the one you picked gets added to your list of tech and you pick a new one, and then there are goals and you can chose one and it will pick your tech for you (based on the goal's requirements)

I was thinking of implementing a system like that in a Text based game im working on, and just seeing what everyone else though.

Also anyone who has played WoC knows that not all Tech gives you weapons or skills, but stat bonuses and such.