Update: The Oracle 12c upgrade slides are available too.
Check out the extensive slide deck (over 500 slides) about upgrading techniques to Oracle 11.2, by Oracle Corp (Roy Swonger and Mike Dietrich):
It has lots of examples (from real customer upgrade cases) in it.
Thanks to Randolf Geist for telling me about this.
You can also download other interesting presentations from that page (check the right hand side download section), like the Oracle Database Behavior Changes 8.0 through 11.2 doc. Pretty cool!
NB! Dates updated: After a 1.5 year break, this year’s only Advanced Oracle Troubleshooting training class (updated with Oracle 12c content) takes place on 14-18 December 2015 and 11-15 January 2016 (I had to reschedule the start from November to December). So sign up now if you want to learn new cool stuff!