When I bring consoles out for freeplay at events, I often run Lords, Gate, Bonk, Valis, Blazing, Parasol, Ninja Spirit, New Adv. Island, Bloody Wolf, Splatterhouse. All easy to pick'up-n-play games with recognizable names.
When I want to be a little "colorful" and show off less well known titles, I sometimes break out Aniki's, Dragon Saber, World Heroes, Kabuki(fighter), Lost Sunheart, God Panic, Spriggian, Buster Bros. I like to put a little limelight on these. It helps showcase the system as not JUST the "bonk" system.
At shows, there isn't time to run a RPG like Ys or even a longer platformer such as Drac X but I would always recommend those to anyone new to the obey faith.
<I have noticed when I run a TED and attendees figure out how to change the games, they inevitably seem to pick the NES port hacks for some odd reason...>