I am guessing that google choses its ads according to the words that are on that particular page, but how can the publisher make sure the ads are relevant? My page http://www.internationalmark.co.uk/ranking.html is a football page, but the ads are often about other things, as the word football is only mentioned once in the title. I can't really change anything on the actual page as it is a table with countries and numbers, but is there something I can do with the meta tag, or is there another way of getting the relevant ads?
You could try section targetting: https://www.google.com/adsense/support/bin/answer.py?hl=en&answer=23168 Also pack your pages title, description, meta, h1, h2 and p tags with your keywords.
if you do section targeting you have to put some keywords related "sports" in that page as description.
I have never really had problems in that regard. If I did, it was a temporary thing. Adsense is excellent for producing highly relevant ads.