NASA's Near Earth Object Program finally has another candidate rock whose Torino scale is positive, even though it's just 1 so far.
Its name is 2013 TV135. It's been observed for 9 days or so. During the recent hours, the probability of collision on August 26th, 2032 – Witten's 81st birthday (he wishes I would never have used his name in this sentence, but I've already heard this comment from him on 9/11/2001 right after my PhD defense) – has grown from 1 in 48,000 to 1 in 14,000.
What is impressive about the object is the diameter, 410 meters. The mass is 90 million tons and the impact speed is 14.9 km/s. That produces 2.4 gigatons of TNT energy.
Most likely, the probability of impact will start to go down, essentially to zero. However, with the probability 1 in 15,000 or so, it will eventually converge towards 100 percent. ;-)
In the unlikely case that the probability will approach 100 percent, the Torino scale will be upgraded from 1 to 4 and 5 and then 9 and 2032 will be celebrated with some regional devastation, something like an extermination of a country. Such events occur once in 10,000-100,000 years.
2007 VK184 is another rock whose Torino scale is 1. The collision in 2048 has odds 1 in 1,500 but the diameter is 3 times smaller than for 2013 TV135.