I worked at BBN (Bolt, Beranek and Newman) from 2006-2008 and was fortunate enough to have a one-on-one phone call with Leo while I worked there. At that time he was in his early 90s, and was still amazingly sharp and full of energy. Even in a brief phone call his curiosity and kindness left a long lasting impact.

BBN was (and presumably still is, though now part of Raytheon) an amazing company to work for even 50 years after its heyday as one of the original contractors on the ARPANET project. I remember getting to meet Ray Tomlinson (who sadly passed this March) and a wide range of others who were instrumental in the early days of the internet. Seeing what was happening in CS research at the time was pivotal for me changing my career towards computer science.

One of my favorite anecdotes about the early years of the company: As mentioned in another comment, BBN started as an acoustics firm. While JCR Licklider was there briefly in the early 60s he got the company to purchase a computer. This was expensive and somewhat out of the scope of the company, when asked why purchase such the thing the response was “this company is full of smart people, they’ll figure something out”. A few years later Licklider was a PM at ARPA in charge of the ARPANET project which BBN would soon become the lead contractor on.

Leo definitely lived to a ripe old age, but he will be missed nonetheless.