A few ink stamps I collected while in Japan this summer.
Train stations in Japan each have an identifying ink stamp (an 'eki' stamp) that can be collected by those passing through. They're also found at temples, bridges, towers, parks, - more or less any 'destination'.
This is a pretty pitiful haul, though my girlfriend's brother Beam has an incredible book full of them.
Here's a good blog post I found discussing Eki stamps: http://denshadejapan.wordpress.com/2011/05/22/the-eki-stamp/