I recommend you search for "beef" and "gravy" over on the BA board.

Last Summer, UK supermarket chain Tesco was offering 50 points in its clubcard loyalty scheme (worth 120 BA Miles) for spending 70p on a disgusting frozen 'ready meal' consisting of beef covered in gravy. Many FT'ers were touring the country buying up thousands of boxes of the stuff.

Other odd things from the UK:

Travelex was giving 3 miles per £1 exchanged - INCLUDING Sterling Travellers Cheques. We were heading out to Heathrow with £3,000 IN CASH to buy £3,000 of UK£ travellers cheques, to pay straight back into our bank accounts, to withdraw again in cash, to take back to Heathrow etc etc

Buying some dodgy biscuits called palmiers, again from Tesco. Plus Tesco instant coffee, mobile phones (which we unlocked and sold on ebay), sim cards and many other products where the company gave out enough bonus points to make it worthwhile.

There was also, again in the UK, a targetted promo last year where MBNA gave BMI credit card holders miles on balance transfers. Some got over 200,000 miles by moving balances from credit card to checking account, paying off the card then starting again.

However, nothing seemed to top the AA Cinemark promo, where some AA FT'ers admitted to 'dumpster diving' outside cinemas to retrieve drinks cups which had a token on them for AA miles!

You should also look for the massive Marriott thread on the BA board. When Marriott let you buy points for 1c each (which they did for about 3 months before canning the offer last month) you could (by converting Marriott points to Tesco and then to BA) get unlimited numbers of BA Miles for 0.8p each. Using the American Express '2 for 1' voucher that is also available in the UK, that basically allowed you to get 2 F tickets to anywhere in the US for £1,200 + tax for the pair, or two J tickets for £800 + tax. The BA FT board must have bought at least 10 million Marriott points between us.