If you meant that you don't want to have to use a web browser (Internet Explorer, Firefox, Safari, and such), there are chat rooms that you can access through Instant Messenger applications (like YIM).
If you meant that you don't want to download an application like YIM (Yahoo Instant Messenger) or AIM (AOL Instant Messenger), you can access forums all over the internet, depending on what kind of people you want to talk to. (I'll put links later in this post)
If you meant that you physically want to be in a chat room (without the convenience of a computer), I'm not sure how to help you, besides telling you to join clubs!
Site with my favorite forum (Gaia Online): [Link](Mouse over link to see full location)
(lots of interesting people who are willing to debate, plus you can make your own avatar-self and profile!)
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