Stuff that they sell though. I could never imagine buying a revolving calculator or a chicken rotisserie as they wouldn't sell them in my local Sainsbury's.
To start of this list (which will be very comprehensive once we get to about 100 replies) I will go for:
1 - Supermalt - that weird drink in those brown bottles. Found in the ethnic food section in most supermarkets (or the "black people section" as my friend and fellow diser calls it.) I can't imagine anyone wanted to drink a cold malt drink.