For what it's worth, I thought I'd offer my tuppence worth.
EC261/2004 - I love it ! As far as I understand the act, and in particular reference to this thread, you should be provided with a printed copy at the airport should you request one. There doesn't even need to be an "incident" - just a simple request for a copy should solicit one pretty quickly.
When a delay does occur, the carrier has certain responsibilities that MUST be undertaken. The actual assistance varies with the length of delay and the distance being flown on the delayed leg of thr journey.
I've personally experienced a long delay (14 hours if memory serves) when hoping to depart Manchester for Sanford in Florida with Travel City Direct (tour op.) on an Excel aircraft (the carrier). Vouchers were provided for refreshments but as the night progressed outlets started to close - eventually, there was nowhere to purchase refereshments. At one point, WH Smith (the last open outlet very late at night) refused to accept the vouchers against the purchase of bottled water. I kicked-off (politely but firmly and vocally) and the purchase was permitted after I provided my name and address to the WH Smith duty manager suggesting they sue me for theft - I'd left the vouchers at the till and departed the shop with the water.
One aspect that I've never known to be provided - and EC261/2004 does demand this - the provisions of one or two free phone calls/faxes or texts. This can be useful if you need to re-arrange transport or inform a hotel of a late arrival.
If your delay exceeds a certain number of hours (other have posted links to the actual regs. on this thread) then meals should be provided. Finally, if a long delay is suffered and the time is such that overnight accommodation should be provided........it SHOULD BE PROVIDED. There's a potential get-out clause in that element though as the act suggests accomm. should be provided if by doing so the delay is not extended.
Transport to/from accomm. and to/from meals (if provided off-site) must also be included.
There's another element that might be worth noting as well. If you are travelling on a "package" (two or more of the following booked through a tour operator: flight, accommodation, car-hire, pre-booked trips, transfers) AND your delay is outbound to your holiday AND the delay is such that you loose a night's accommodation at your destination hotel you can claim one day's worth of the ENTIRE PACKAGE COST from the tour operator.
So, a seven night holiday costing a packaged price of, say, £960 would provide you with a compensation claim of £137.14 if you were delayed outbound by one day. Add £50 per person to this for inconvenience, distress etc.
I do not believe this applies to homeward bound legs at the end of the package holiday.
This last point was the element that Ros succeeded with when she handled my case against Travel City Direct over 2 years ago. And a great job she did as well - at a most acceptable cost given that I'd been able to obtain a much lower level of compensation offer from TCD prior to her involvement.
There's some helpful folks on this site - but, sadly, some plonkers as well. The latter can add a bit of spice, the former help solve the real issues though.
Mike