I heard this a lot from teachers. Strategies or systems have ranged from drawing names out of a hat to having Popsicle sticks with names. Personally, I like "kidpicker" which randomizes drawing of student names for discussion tasks, or group work.
|The kidpicker app that you can bookmark. Periods or class appear in the drop down menu|
Kidpicker is a google apps script developed by Andrew Stillman and you can see the link here. Upon visiting, you can install the script in your Google Account which sets up a spreadsheet in your Google Drive that you can populate with names if you have multiple classes or want to randomize from smaller pools of students.