oriental trading carries a product called choco-rocks they're candy coated chocolates that really look like rocks. they'd be good in the goody bags
http://familyfun.go.com/recipes/special/cake/cake_volcano/ this is a volcano cake but if you leave out the lava and add a rock climber it could work for your party
will they actually be rockclimbing? or is that just the theme? i will try to think of some games and post them later
good luck
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