Today is the (the SS+K's 19th birthday (where I work), and coincidentally it's also Foursquare Day. Some background first: my co-workers and I happen to be somewhat obsessed with Foursquare. We have 18 different micro-locations in our office, and people are constantly battling for mayorship- so much so, that last year we created our own Mayorshup, a Risk-board of sorts for SS+K'ers to battle each other for supreme SS+K office mayor.
Foursquare-powered birthday card. When someone checks in to any of our office Foursquare locations, they "sign" our card by adding their Foursquare profile picture to our emblem, and adding their username to our card. The card is of course viewable online on our site, and also is being displayed on a giant lcd screen in our cafe.
We've also opened an SS+K Foursquare Labs page to host the many Foursquare hacks + projects we've launched in the last year. This whole thing has been a pet project of mine, so I'm really excited for it to be live. Thanks to everyone (@alvvvvvin @brainpuppy @FirefallPro + more).