If you're looking to make yourself somewhat more productive on this lazy weekend, and you've got an Arduino or two collecting dust, we've got just the thing to add line after line to your dwindling to-do list. Tronixstuff has a borderline insane tutorial series going, and as of now, 27 chapters have been published. It's essentially the Arduino Bible, but the two most recent additions in particular have piqued our interest. With the explosion in mobile broadband, even hackers are looking to get their creations online. If you've mastered the art of Arduino, but haven't yet been brave enough to toss in a bit of GSM communication, the how-to guides linked below definitely deserve your attention. Just be careful how you write that code -- one wrong line with a SIM card installed could lead to text overages that'll take two lifetimes to pay off.