This is a great way to pair up students quickly, but at the same time giving them to opportunity to choose their partners.
First, you hand out this sheet to each student. Then, give them about 10 minutes to find a different partner for each time on the clock. Then, when they have completely finished filling the clock out, ask them to bring it to class each day (or just store it yourself).
When you need them to pair up for any kind of partner work, just ask them to meet with a specific time. For example, I would say to my students, "Meet with your 2:00 partner!" And then they would look at their sheet to see who is in their 2:00 slot.
It's quick, simple, and fun!