Increasing the drop rate on grenades sounds like a dangerous thing in real life. For Gearbox's shooter RPG Borderlands 2 however, a boosted drop rate is a lovely event, even if it's only for a day or so.
The increase is to celebrate the upcoming release of "Sir Hammerlock's Big Game Hunt", the game's third lot of downloadable content. According to this blog post on Gearbox's website, grenades might not be the only item getting a transient boost in drop rates during the game's so-called "Gear Up Weekend" and we should expect more news tomorrow.
Respecting the game's availability internationally, the blog post includes links to timeanddate.com that will convert the US times and dates into local versions automatically. I'm not sure how long Gearbox has been doing this, but I'd say all major developers who hold these types of events should take note.
Also of interest is that Gearbox has the ability to tweak drop rates for Borderlands 2 without the need for a patch — you have to be connected to the internet to benefit from the change. Makes you realise just how connected games are these days beyond DRM and multiplayer.