What you do is make it a fun night instead of a big money night. Here is what we did to change things up and introduced new games in. We usually are a 1/2 NL holdem with a 50 max buy-in. You can rebuy back up to 50 if you go below 20.
Make an announcement at the end of your game that next time we will be playing X game instead. This will give them time to try and look up how to play and maybe even practice some before that night. Nobody likes a suprise.
Make sure you know the rules and how to deal the cards. Explain the rules right away and how the game's betting goes. Make sure if you play razz you truely understand who is the winner for each hand and everyone understands how you read a low hand.
Do one round where it is free so everyone can get a feel of how it works and how the cards will play out. Here is where you can show how to read low hands
for razz or omaha hi/lo.
Once you start the cash game lower the bets by at least 1/2 for the first night or go straight limit betting patterns. That way you are not risking as much as for a game you are not as comfortable playing. We dropped our blinds to 25/50c for omaha and played 25c/50c limit razz.
Once they feel comfortable (usually the second time you play) you can move the limits back up.