If you have a boy who doesn't want to read a science fiction book for a class assignment, ask if he liked Monty Python. Then give him Adams. There's a weird crossover, like boys who like horror books also reading about WWII, and girls who like vampire books also liking problem novels. I just got a copy of the fifth book and am reading it, but none of it is sinking in. Instead of a review, here is a list of the series, as well as the official Adams site. Sadly, this author passed away in 2001.
The Hitchhiker's Guide to the Galaxy
The Restaurant at the End of the Universe
Life, the Universe and Everything
So Long, and Thanks for All the Fish