The latest edition of Circus of the Spineless is up at the Neurophilosophers Blog. It’s packed with more invertebrate goodies that you could poke a stick at. (But I suggest you don't go poking sticks at it willy-nilly. There are spiders and bees and all sorts of things that could get you back.)
And on the subject ... there's also a video of mating leopard slugs (Limax maximus).
Make sure you have a roam around the Neurophilosopher's blog. It's stacked to the rafters with fascinating articles.