OK, here's my two cents.
1. Buy Paranoia XP, the Mongoose edition published around 2004. Same flavor as older editions but with a simply d20 roll under mechanic.
2. Run "Mr. Bubbles" found in said book. Great intro adventure.
3. As far as setting, explain the basics that players need to know so they don't lose characters too quickly: Clearance, Troubleshooting, Secret Societies, Mutations, Alpha Complex, The Computer, IntSec, and especially, why it's ok to be a PC killer in this game.
4. As far as rules go, explain the d20 roll under mechanic, using mutations, Perversity Points, six clones, and how the GM is always right.
5. Play! Laugh! Get revenge!
If everybody had a good time and wants to play more Paranoia, I recommend buying the following books as time/funds permit:
- STUFF and/or STUFF 2 (equipment guides)
- Crash Priority and/or WMD (missions)
- Service, Service (missions, NPCs, and setting info)
- Criminal Histories (character creation add-ons)