In reply to hokkyokusei:
Huaraz in Peru, in particular Andea Kingdom is a good place to meet people. There's a board you can out your name down.
Patagonia wise there are two places, El Chalten which there is the climbers hostel (The Hem) and Bariloche where just go to the Frey and hang out at the refugio. You'll meet someone there to climb with.