So I have to do a lot of reading for school, and I'm not the fastest of readers, which means a lot of time reading.

What are some possible exercises to do while reading?

Squats is one.
Calf/Shin/Ankle.

What else?

Reading and stretching might be a bit more reasonable than reading and working out. When you're working out, you should focus on what you're doing. It'll help prevent injury, and you'll learn to be more in tune with your body.

Zac's full of great and interesting ideas.

I don't mean to come off brash here, because you've definitely shown you know how to train alec! Even in your examples, though, I disagree.

IMHO it makes you go longer because you aren't working as hard.  Even with stretching...i don't see the benefit of reading...because it will not allow you to push as hard into your range of motion.  You make progress with stretching when you push beyond what you can do normally...this causes pain -- pain will make it impossible to concentrate on a book/tv.

When you are training hard, the part that processes things like reading, math, reasoning -- it all just "turns off". 

Any training that will cause a benefit will require you to work hard enough where reading becomes a chore.  If you focus on reading you will therefore not be focusing on what you are doing.

Here, try this test.  Cycle with the goal of going as far as you can in 10 minutes.  Two days later, repeat the test but do it while reading a book.  Don't look at the mile counter on the exercise bike until you are totally done with your 10 minutes.  I bet you the time is significantly slower on the trial where you were reading.  Since the most gain/benefit in human performance is seen on expressions of power (More Work in the same time) this would directly prove that reading during exercise is holding you back.

the point is that you won't get very much out of your exercise if you are trying to read (and comprehend) something while you are doing it.  you are better off letting your body recover from your previous workout by relaxing and enjoying your book, imho

Yeah, rest is quite important, too. In that case, I'd still recommend stretching so you can recover but also potentially increase your flexibility. If nothing else, just make it a relaxful stretch, much more like a cool down stretch than that done to improve flexibility.