(Please click through to Think Geek. They might be having a sale!)
Hogwarts may have passed up the absolute privilege of teaching us witchcraft and wizardry, but we still like to keep some trinkets around as memories of what could have been. A potion bottle, for instance. Pretty easy to carry these suckers around. The problem is, we don't actually know any good potions since we weren't trained so it isn't very useful. But we can absolutely change that with this keychain...