Rocksmith is outstanding, it really is. By smooshing together Rock Band and an extensive virtual suite on how to play an actual guitar, Ubisoft have created a gamified marvel. The Mac Stoire currently has the 2014 version of the game down at around £8.82, but you're paying for a Steam key, so PC owners can take full advantage of this deal too.
If you're yet to acquire a Rocksmith Real Tone cable -- the interface that allows you to plug your guitar into your platform of choice -- it could be worth shopping around the marketplaces for a bundle deal. But you can pick up the cable for around £15-20 on its own, and there are still plenty of retailers stocking the solus version (without the cable) for upwards of £30, so this is still a pretty damn good deal.
Thanks to jaystan at HotUkDeals.