I've picked a couple of systems to learn that I think will give me a variety of things to do at Gen Con without breaking the bank. Here's my thoughts...
I've picked up the Pathfinder Core Rulebook. I didn't know it until I started reading it, but clearly this is where the AD&D style play that I am most familiar with has gone. That's convenient. I'm reading through it right now because I'm so old school that skills and feats are a new idea to me. Still, everything looks fairly familiar so far, but with good modifications. It looks like they've really balanced out some of the things that never seemed correct to me in AD&D. I haven't gotten to the combat section yet, but peeking ahead makes me confident that the round/turn system now makes sense and is way easier to implement. I look forward to digging into it more.
I also picked up the 4E Dungeons and Dragons Players Handbook. This looks more like a radical rewrite. Still, I see the potential and think it will probably be a lot of fun, if in a different way than Pathfinder. I also consider D&D to be a need-to-know system for Gen Con since there will be so many opportunities for games. I look forward to diving into this in the coming months. I'd like to make it to a few D&D Encounters games prior to Gen Con as well.
Roleplaying games are fine, but what about some lighter fare for quick games and cheesy fun. Gen Con is a 24 hours-a-day event after all. Munchkin looks like a great start there. I got the starter set, and reading the rules made it sound like a fun little social game. When I actually set up a solo game (where I played all the hands just to get a feel for the rules and the flow of play) it became very obvious that the fun lies almost completely in the interaction. I can see having a blast with this when there's some downtime. I may even grab a few expansions so I have those on hand.
I'm hoping to also grab Cthulhu Dice and Zombie Dice. These seem to be really quick, play anywhere games that can be over in minutes. It's good to have a few of those handy.
I'm open to other suggestions as well. These are just some games I decided to learn since they give me a good arsenal of games I'm ready to play.