I have never been on David Letterman's "stupid human tricks". However, I have a variety of stupid tricks I can do that may one day get me invited. Unfortunately, nothing I can do is very original.
My first stupid trick is making my tongue do the wave.
My second stupid trick is blowing spit bubbles off my tongue. (Must have correct spit consistency in mouth. Temperature, barometer and humidity must also be just right for me to perform this trick.) I actually learned this trick when bored one day tracting rich summer homes in the Poconos.
Placing my entire fist in my mouth.
Dancing like a complete moron.
(Dave, if you read this post, put a note in the comments and we will schedule a time for me to come perform.)
Oh, one other thing. I know the entire "Small Wonder" theme song by heart. Question: Who does the Small Wonder dad look like?