please explain cache?

this may be a simple question but just want to further understand for myself,
im not sure what the cache's on cpu's actually mean?
i guess that a bigger cache is better but not sure why or what for.

CPU cache
http://en.wikipedia.org/wiki/CPU_cache

In short - say you need carrots. You check the fridge first. If there are carrots there, awesome. If there aren't any, you have to take a much longer trip to the store to get some. It'd be convenient to store the entire grocery store in your fridge, but the fridge is too small.

Your refrigerator is the "cache". It can get a lot more technical than that, but it's not the worst analogy for getting a feeling for how it works.

thanks for the link to wiki didnt actually think to look there (for once),
and thanks johan thats a good simple analogy helped me understand the theory.