I was thinking four buttons, whoever presses it the quickest that info is sent over infrared to a receiver where an led will light to show who has pressed their button.
Unless you have a separate, widely-spaced receivers for each transmitter you will run into conflicts. Encoded IR transmitters/receivers take time to transmit, receive, decode, and react. If two transmitters trigger at near the same time they will interfere if there is only one receiver or closely-spaced multiple receivers.
The problem is you need a way to encode on the transmitting end, and decode and display on the receiving end. The [first-locks out-others] is easy. I've used variations of: http://www.techlib.com/electronics/games.html The indicator lamps could be LEDs in photocouplers that trigger buttons on a hacked TV remote. The receiver end is more complex. You can get a kit to do this, like: **broken link removed** Or you would need an IR detector and a microcontroller.