Random Team Generator

I am organizing a sports tournament and would like excel to randomly generate the teams for it.

We have 20 people who will be organized into 10 teams of two.

What I am looking for help on is how to setup the formula to have two people randomly paired together without duplication. The names will be further used in other formulas for points calculations.

So, I have the names as A1:A20 and then would like the teams generated from B1:B10 and C1:C10 with the team being the row and the team members in the B and C columns.

Thanks!

Brett