Here's a really cool buzzer app the entire "Family" will "Feud" over.
 
It can not get much simpler than this!
The control screen has one toggle button "Off / On." The left arrow key triggers the left side of the screen. The right arrow key triggers the right side. The first button hit will lock out the other.  But just because it is simple does not mean it isn't super smart. If you are on a single screen display, a button pop appears on the control screen that allows you to hide the window. Perfect for playing on a laptop or single screen setup.

Here is a video of Brian and Brad playing with the Buzzer app and some fruit.

For more info on building your own button, check out "DIY Gameshow Buzzers"
Use a MakeyMakey (sold separately) to connect physical buttons.
Buy some wireless Affordable Buzzers here.