Well thinking about the random name generator reminded me of another way of calling on students--this time the old fashioned way. And I have to give credit to this idea to my dear friend Megan who moved to the land of VERY FarFar Away...
Get some craft sticks/ popsicle sticks. If you have just one class, write students's names on the sticks. Drop them all in a jar/ can/ container of some sort. Draw out names to call on students. You can leave the sticks out once you call on a student or replace them in the can--that way students never know if you might call on them again.
But in my situation teaching in the library, this is difficult if not impossible to do. I have classes come in and out and sometimes I may only have 10-15 minutes with them. But I could use a jar of numbered sticks--assign students a number and call on the numbers. You could put numbers on the desks/ tables where they will be sitting or hand out "tickets" with numbers on them as they come in the room. The idea is to be able to randomly call on students and make it easy to deal with multiple classes.
If you have any suggestions to help to engage students in lessons, I'd love to hear them!