virtual host in one ip address

I have a rackspace server running with nginx. I am a newbie to all the server stuff. Let me explain the situation here:

1. I have an IP address and I have two virtual host on my machine.
2. I don't have a domain and I don't want to buy one
3. I want to map it so I can access the website as xxx.xxx.xxx.xxx/v_host1 and xxx.xxx.xxx.xxx/v_host2

How can I do this the easy way? I am guessing I should change the nginx config of my site... but not sure which one to change.