Teaching a Triathlon Class!

If you can get some bikes and helmets you'd be good to go, but with out at least bikes it will be very tough. Practicing taking on and off your shoes would be pretty mundane. You would probably want to just change it to a running class.

you're going to need a transition bucket...

Well you could teach what you know about the four disciplines... running, swimming, transitioning and biking.  You can talk about proper diet, sleep and taking care of injuries/injury prevention.  Are there any local kids triathlon events that the club might set a goal of doing next year?  Help them come up with a training log they can use to train. 

This sounds like a really cool opportunity.  Maybe you could get some local elite triathletes to make appearances, Q&A session, talk about gear, their training, experiences, goals, etc.  You might even chat with local tri/bike/run stores, it seems there should be some interest in helping the younger crowd get interested in this sport before they are middle aged.       

Perhaps contact your LBS and see if they have any bikes they could donate (don't forget about helmets), or if they would post a "donate your kids old bike" signs.  Those bikes could then be donated to a charity or for the upcoming Holidays in a few months for those in need.

The most important thing is to make sure you get the point across that it's all for fun, that you compete against yourself and encourage everyone else to do their best too... even the people passing you   Too many sports these days are about hoping the other guy sucks instead purely about you doing your best regardless of everyone else (which is the thing I love the most about Tri)

Do you have video/computer equipment available. Show them so IM videos, some kid triathlon videos, etc. There is a great one about a 9 year old girl who did an olympic tri with her Mom for her dad who has pancreatic cancer. She raised 30K and Simon Lessing ran the end of the run with her.