198 National Olympic Committees have participants in the Rio Olympics so I'm charging just £1 a pop for countries. There are two equal prizes for whoever tops the medal table at both the Olympics and the Paralympics.

Cost per country: 

£1 donation = 1 country

£2 donation = 2 countries

£5 donation = 6 countries (1 bonus!)

£10 donation = 12 countries (2 bonus!)

£20 donation = 25 countries (5 bonus!)

How to play: 

Bring me your money in cash.

Text RIOO50 £(amount) to 70070. NB: The first two are letter O's in RIOO followed by a zero at the end of RIOO50.

Alternatively, you can donate via card or PayPal on this page.

If you text or donate online, be sure to let me know you've done it so that I can give you your country/countries.

Prizes up for grabs:

Top of medal table at Olympics gets: 1/5 of the total raised (prize capped at £25 maximum)

Top of medal table at Paralympics gets: 1/5 of the total raised (prize capped at £25 maximum)

Macmillan Cancer Support gets: all proceeds, ie a minimum of 3/5 of the total raised

About JustGiving:

Donating through JustGiving is simple, fast and totally secure. Your details are safe with JustGiving - they'll never sell them on or send unwanted emails. Once you donate, they'll send your money directly to the charity. So it's the most efficient way to donate - saving time and cutting costs for the charity.