Test yourself on the fruits in Welsh.
Just as your five (fruit and vegetables) a day is good for your body, learning another language is good for your brain.
So, while you are wandering around the supermarket and doing your weekly shopping, and wondering what to buy, and why someone else couldn't have done the shopping for you, you could practice your Welsh food words.
You could be in Tescos, Waitrose or Asda. It doesn't matter (although Waitrose is more expensive), but it will help if you are shopping in the fruit and veg. aisle for this particular exercise.
Simply try and name the fruits in Welsh. It will be more difficult than you think, but introducing language learning into your daily life is an effective way of learning in otherwise wasted time.
This is easier if you live in Wales, as you can just read the labels. But that's cheating;)
See also the names of Vegetables in Welsh, general food words, and words for meat.