For me, if I am not feeding my brain some sort of interesting information or stimulating it in some way every single day, I feel different. It's hard to describe, but I just don't feel as productive or as human that day.
That's why I listen to podcasts on my morning commute. That's why I've been trying to blog every day. That's why I try to read an intelligent article or a chapter out of an interesting book as often as I can. Sometimes it's as simple as watching a documentary instead of a rom-com. Or sometimes my husband and I will play a game of Scrabble instead of watching TV at all. I engage in interesting, challenging conversation when I can.
I know there are a lot of other fun and interesting ways to keep the brain stimulated. Doing a normal activity like brushing teeth with your non-dominant hand, doing a puzzle, and trying new types of physical activity can all assist in growing our brains. Socialization is also extremely important especially as we age.
Of course I still spend plenty of time consuming the mind-numbing information, but the little things I do to feed my brain add up.