Congratulations to Curtis Cooper of GIMPS for finding the largest known prime (for now!). Are you ready? It’s a Mersenne Prime and apparently it took 39 days of computations to verify its primality. Here it is:
And here’s a nice write up on CNN. (HT: Zach Kram, Prisca Chase)
Random Walks 
Mr. Chase! The largest known prime was found again! It’s another Mersenne Prime! Yay!