* Moscow 2013 to Heathrow -- 4 more hours in the lounge, got €600 compensation.
* Heathrow 2014 to Bangkok, 5 more hours in the lounge -- got €600 compensation.
* Toronto 2017 -- delayed Delta flight to New York to catch a Virgin flight to Manchester so was downgraded and rerouted on KLM. No compensation as it was a U.S. airline. Lesson learned. (No lounge access either so cost me several beers)
I wasn't flying during the Volcano incident.
I do remember being delayed overnight with ryanair due to weather, but that was c. 2003. They wouldn't reroute me on the next morning flight to Anconna (rather than my original Forli flight -- only 50 miles away), so I had to buy a new ticket. It's attitudes like that which is the reason EU261 came in.