The things most interesting had to be postponed - the nitrogen I got was far from liquid, so the superconductor-experiments couldn't be done for lack of cold.
Stupid story - the master-gas-vendor had no containers in stock to rent out, so I contacted a related sub-vendor who ignored every mention of "liquid" (in the email-order's subject and body, on the telephone, in person when i picked it up), and gave me the only kind they carry ... gaseous.
So we preponed the Martini-hour and had more time to try and grasp some theory.
Luckily there is prospect of borrowing the superconductors again at a later date, probably fall. But next time I'm going to "practice" getting liquid nitrogen ... I think about getting some to just "cook" some time this summer.
Link to photos on Flickr.