Guineas as a unit is still used in horse auctions. The buyer pays in guineas ie £1.05, and the seller gets the same number of pounds. The auctioneer takes the difference as commission.
Edit: strange feeling of deja-vu when I posted the above. Turns out I posted the same thing a week ago on this very thread!
We use liters per ten km. Although the car display shows liters per 100km, but since I’m quite able to divide by ten in my head, that’s not really an issue 
A “metric two-by-four” is 48x98mm.
Standard metric teaspoon = 5 ml
British ‘Imperial’ teaspoon = 5.91939 ml
US ‘customary’ teaspoon = 4.92892 ml
Standard metric tablespoon = 15 ml
British ‘Imperial’ tablespoon = 17.7582 ml
US ‘customary’ tablespoon = 14.7868 ml
standard Metric cup = not really a thing, some crazy US-influenced countries use it as shorthand for a quarter-litre
British ‘Imperial’ cup = no such thing, that’s what half-pints are for
US ‘customary’ cup = for some reason it’s needed because half-pints just won’t do and it’s 236.588 ml
Note the weird mind-meld between the americans and the metric-ans on the proper size of spoons, with the Brits ploughing their own crazy furrow.
Whereas the Brits and Metric-ans agree that cups are crazy nonsense which only Americans and their neo-colonies could love.