At the school where I teach audio engineering we made a reverb impulse from a large (ca. 2000 m3 empty concrete hall) by popping a balloon and recording the reverb response with in-ear microphones (Roland CS10-EM). I loaded it into Pianoteq in the reverb panel and it sounds great, especially on headphones.
I explore 2-5-1 progression jumping between keys completely rubato, just fooling around essentially, but it was very fun!