The E3 countdown timer (at this posting time positioned in the top-left) is for the Electronic Entertainment Expo. For those not familiar with this event, E3 is a convention where, among other things, major video game companies unveil their new consoles and video games.
E3 Logo
Last year, Nintendo unveiled the 3DS. This year, they will unveil "Project Café," their next console (don't worry; the name "Café" is temporary.) This also coincides with the 3DS's first major system update. Included in it will be a web-browser, the new "eShop," and more! The eShop will include downloadable games, with Super Mario Land and The Legend of Zelda: Link's Awakening being released at the eShop's launch. It was also hinted that a slightly enhanced friend system will be included, perhaps with a way of sending your friends messages over Wi-Fi.