I read a lot of technical material for my job (physicist) and find that trying to make it as 'active' as possible is key to making it enjoyable. I made a list of actions that make it active, things like 'visualize the material' or 'draw a concept map' or 'make a prediction about the material, keep reading, and correct the prediction' or 'what do you already know about this material' etc etc., and find that going down the list in a random fashion has helped make it more interesting and engaging.