A few years back but I too was flying SQ Singapore - Zurich. About the time I expected to be greeted with breakfast - the Captain came on.
"Ladies and Gentlemen - If any of you have had the opportunity to open your window shades - you will have noticed that the sun is on the wrong side of the airplane."
Turns out he had to shutdown one of the B747's engines, somewhere over India, and had decided to head home, rather than divert. On landing at Singapore we too were given an envelope. Boarding cards for the rescheduled Zurich flight (with another aircraft) and connecting flight from Zurich. Voucher for a meal at Changi, an invite to the lounge and voucher for telecalls from the lounge and a nice letter of apology! Got home about 18 hours later than expected but their 'recovery' was excellent.