@JamesJenkins raised this up in chat, so credit his forward thinking here, but given that we're coming up on our very fist anniversary it feels like we should do something to mark it, and not in the traditional manner of our furry friends. So what do you think? Any ideas, suggestions, comments? Am I nuts? Wait, don't answer that!
You've all worked extremely hard, so come up with something like James had suggested, but shoot for something that everyone can do. Funniest pet photo taken after a certain date might be neat.
Stage it here on meta, with the guidelines, direct folks to chat if they want to be social about it and I'll make sure to throw some Stack Exchange swag behind it to make it all the more festive. Just feature the post, it'll show prominently enough on the community bulletin.
Don't go looking to accomplish anything other than people ordinarily using the site having a bit more fun. Content generation and the like generally doesn't suit this type of event. To be clear, everyone that helps make it fun will get something.
So, go nuts, just keep it fun and make sure it doesn't go as far as being annoying for those that don't want to join in, and I'll make sure you get some stuff to ice the cake.
Following on the suggestions above, how about a "your best/funniest/heartwarming pet story" and encourage people to explain the story with pictures? That way you don't necessarily have to be a camera guru to participate.
Hopefully people would then participate and we should encourage the story to be about their pets (rather than generic). It may even lead to a permanent weekly/monthly header contest, who knows? Some sites, like the Photography site, have a rotating banner image from a ongoing contest in meta.
We can have a contest for the oldest pet (by species?) owned by members of the site. As there is not a good way to drive members to meta or chat, would probably need to occur in the main space.
We could celebrate everyone's animals as well as our own. We can also celebrate new users as well as pets that have problems. We can also talk about each others pets and what our and theirs do and stuff, etc, etc. I agree with James that we should take this too the chat as the main site might be a bit cluttered of a lot of people. I also think we could also boost some animal questions and answers up a bit on the main site. Thats really all I can think of.