I was lucky enough to visit the museum at the end of 2019, just before COVID-19 hit and the museum had to shut down. Unlike the Computer History Museum in Mountain View, the machines here were fully operational and you could actually get to use them - I compiled some hello world code on a NeXTcube and I still remember that fond moment. IIRC they had systems that you can SSH in and use, but seems like they've taken that down. Must be a recent thing since I remember they were operational a year or two ago.