Few days before christmas I was flying SFO-IAH-LHR-FRA with the IAH-LHR leg upgraded to C with a GPU.
SFO-IAH was oversold by a lot (they ended up taking at least 6 volunteers, probably more, and were still looking). Only offering $200, but they offered to put me on the direct SFO-FRA in business. Of course, they booked it directly into C (well, D), so I had no problems upgrading to F
A few hours sitting in the SFO IFL, a double-upgrade to Global First class, arriving several hours earlier than planned, and a $200 voucher. Probably my best VDB to date