Facebook - Offers pirate and upside-down versions of english as language options.
iOS 6 - When selecting new wallpaper, preview screenshots show a realtime view of your current home & lock screens
/via Rich Cornish
Foursquare - In the iOS notification settings, the option to include adorable puppy photos in weekly updates is given.
Skype - Changing the default chat font to Comic Sans makes the smiley sad.
Google Voice - Can either send you an email or auto-recharge when your balance gets below $2.00.
Reeder for Mac: Settings window turns semi-transparent when changing appearance settings.