Tomorrow is PixelJunk Monsters: Ultimate HD day for PlayStation Plus members. They're getting the game for free on PS Vita once the PlayStation Store update rolls out.
This is a tower defense game -- among the best, if you ask me, and one of my personal favorites right up there with Immortal Defense and Defender's Quest -- that has updated visuals, touch-screen controls if you'd like, the content introduced in the Encore expansion, and more.
Speaking of reasons to hop onto PlayStation Network, I hope you took full advantage of the weekend flash sale that had a bunch of games on sale for $0.99 each. I got Everyday Shooter!
PlayStation Plus: PixelJunk Monsters Ultimate HD Free for Members [PlayStation Blog]