HI, we have a hackerspace in Nelson.BC Canada, http://www.nelson-tech-club.info/ and have a Science fair coming up, we only just found out about it and it is on April 13th. We have ten members and various arduino skills. We want to impress visitors to the booth with interactive Arduino builds so we would welcome any suggestions for stuff we can build and run fairly quickly that will impress all ages, obviously a bit more than one LED (13) blinking away !!! HELP.we don't have much time. We do have a forum if you are local and might join. 
- Robots - things that move
- Sensors with readouts - e.g. a home heating simulation - (temperature with a potmeter, leds to indicate pumps)
- distance sensor coupled with piezo -> closer is higher pitch => music !!
- ...
Have a look at my blinkenlight experiments. IMHO the LED camera LED Camera | Blinkenlight and the Thermal Imaging | Blinkenlight are the most impressive. However according to my page statistics the knight rider effect Knight Rider | Blinkenlight gets more hits than I would expect. In my opinion the heartbeat Heartbeat | Blinkenlight is more impressive though.
All effects are very easy to set up except maybe for the thermal imaging. This is because the later will not work well on breadboard.
Thanks for both replies, just finished Knight Rider, looks good for kids to see.
I have found this simple project is good for shows:-
http://www.thebox.myzen.co.uk/Hardware/Sneak_Thief.html
At the NY Maker Fair last year I had candy as the treasure and if you got it out without sounding the alarm you got to keep it.
Thx Grumpy_Mike will get right on this one, looks like fun.
Hi,
If you have the space, a radio controlled car with lap timer. If you use a small cheap car you could run it on a table top and offer the car as the prize for the fastest lap.
Having said that, there are not many Arduino project cooler than the 'Audino'
Duane B
Duane, incredible web site, I have about 10 electric RC cars and two tracks and have been working on a lap timer but am a total noobie still at Arduino etc, any chance you would do a full "Instructable" on the lap timer??
Hi,
Thanks for the feedback on the blog.
I have two major todo items on the lap timer, one is to migrate it to a standalone Arduino so that it fits in a small enough case to strap to a go kart steering wheel. The other is to finish the user interface so that lap progress is shown on screen and to add two race modes for RC Cars -
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Time Attack - which I sees as a configurable number of laps in which to set your best time, timing starts from a start/finish line with an audible count down to the session start.
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Qualifying - this time its a configurable number of minutes to set your best lap, its a rolling start, and timing starts from the first time the car crosses the start/finish line.
I expect to make the code and circuit available once I have finished it, I have really enjoyed using the current version, its so much more fun lapping a track with instant feedback.
For anyone thats wondering what we are talking about, its this -
Duane B