For a limited time, you can get a low cost additional ticket to 5 Cirque Du Soleil Las Vegas Shows.
Get a second ticket for $25 when you buy one at full price for any of the Cirque shows in Las Vegas. Go to CirqueDuSoleil.com for details. Note that you must buy tickets to the same show to get the second one for $25.
Limited special tickets are available per show, so it is important to book in advance.