The most interesting thing about Candy Camera is that you can see, in real time, how some of the different filters that it provides will look without having to take the photo. You just have to slide your finger along the screen to flip through the different available filters.
Once you've taken the photo, of course, you'll have even more possibilities available to you. You'll find all kinds of stickers to decorate the photos, as well as different frames and post-processing filters.
Candy Camera is a relatively good app. While it is designed along the lines of Instagram, and in many ways it's better than Instagram in terms of editing and personalizing photos, it doesn't have an integrated social network. So, you can share your photos on Twitter or similar networks.
Requires Android 2.3.3 or later.