1. Watch Class.
2. Read The Power by Naomi Alderman.
3. Listen to Adam Buxton's podcast.
4. Play the New York Times Crossword app.
"The big ones are very hard (and get increasingly harder)," says Remee, "but actually the mini and midi crosswords packs are really great (some packs are free some you have to buy). They are a good way to challenge yourself while on the tube, but also not hard enough so you feel like a dumbass! Always makes the commute go by really fast!"
Get it for iOS here.