I know a fucking ace blag for a certain diy chain, but I can't tell you cos you'll all be at it, and they'll cotton on. Sorry dudes.
If you're ever eating in Wetherspoons though, complain about the meal, say it's fucking cold or the chips have been microwaved or sommat. Say you're not happy with the quality of food/service, don't back down and they'll give it you on the house. I used to work in their pubs and got to know some of the chefs who told me it's company policy to keep you sweet like. I've tried it and it true.