In the past I've posted pictures of all sorts of mini amigurumi that I've made for the Christmas Bazaar at my son's school. I've been a bit lax over the last couple of years - I've got lots more photos ready to post, but I'll start with a couple of free patterns for things I've posted previously: http://www.craftster.org/forum/index.php?topic=337120.msg3898960#msg3898960
Every year I've made slightly different versions of a mini monkey, but these ones from last year are the ones I'm happiest with. There's a little variation - you can make them long legs or use the alternative instructions to have them sitting down with their little feet sticking out. Either way they're about 2"/5.5mm tall, not including legs.
The little frog is made in a fairly similar way, but is even smaller, just 1.5"/4 cm tall.
Both patterns are pretty simple to make - there are no parts to sew on, you just have to embroider their eyes and mouths to finish them off. Click at the bottom of this post to download the patterns, and have fun with them!