Fun

 Books, puzzles, and games are a great way to improve abstract thinking! Here are a few of my favourites.

Books: 

The Hitchiker's Guide to the Galaxy: One of Douglas Adams 'trilogy in five parts' - he couldn't stop writing them! A radio play that is great in print or audio.

The Lion, the Witch, and the Wardrobe: read the whole series if you like them :)

The next books are a bit more intense, but if you haven't read the books listed above, don't skip them just because you're a bit out of the 'target audience' age range - they are great at any age, and important for future skills.

Out of the Silent Planet.... another series by CS Lewis, sci-fi/fantasy this time - you'll be hooked and end up reading the trilogy 

The Count of Monte Cristo, Alexandre Dumas: amazing, and a must-read for great essay-writing skills in the future (same goes for the Oscar Wilde books listed below) .

Dr Jekyll and Mr Hyde, Robert Louis Stevenson - amazing that this is the same man who wrote Treasure Island - also a great book

The Portrait of Dorian Gray, Oscar Wilde - then read the short but hilarious play The Importance of Being Earnest - check the publication dates, and the deliberate spelling of the main characters (sort-of) name, "Earnest"

The Chrysalids, John Wyndham: an amazing, book - not long, and he wrote others if you enjoy this one!

The War of the Worlds:  This is a radio play (about an hour long) and listening instead of reading is not cheating! It's nothing like the recent movie - listen to Orson Welles himself, the wonderful production done by the crew from Star Trek, or any version you can find! Then look up when and where it was written - it may surprise you!

I, Robot: the real version is actually a short story - the movie captured much of Asimov's concept, but print always adds depth, and Asimov's ability to see the future is amazing - again, check the original publication date - you will be amazed by what didn't exist yet when he wrote it! Fun facts: Asimov also commissioned a graphic novel - of which I own a copy, if anyone would like to read it  - and Asimov, along with Gene Roddenberry, were two of the original creators of the sci-fi channel.

Foundation: 3 short, fast-reading but amazing books, Asimov later expanded the series into many more... continue at your leisure :) - head games from start to finish