Continuing on this daily blog topic of RPG's, thanks to this guy:
4. Most Recent RPG Purchase
I had to fight the urge to run down to my FLGS and buy a copy of the blue Basic D&D rulebook yesterday, just so I could have today be the same answer. But...
I suppose you could count the new edition of the D&D Player's Guide that I pre-ordered, but since I don't have that yet, I'll have to go with Shadowrun, Fifth Edition. This was a "Free RPG Impulse Buy" that has the added detraction of having been really expensive to boot. Wrong game for my gaming group, I think.