I am surprised I did not mention this before. The all-time fun and interesting online game is Guess-the-Google where you look at a set of images and try to guess the WORD that applies to them all.
Go to Guess-the-Google and try it.
What it is doing is testing your ability to find the right search term - what Librarians would call "Keyword" or "Subject Term" and what might be selected by professional indexers if they were indexing a site. In Google there are no indexers. The raw text for part of the site is used for input (word by word) to the search engine.
So use this with your friends or use this in the classroom to get at the issue of choosing the right word to describe a set of items. This is the skill - a word game -- that is crucial to you finding what you need when you do either a Google search or when you search for articles in library databases.